I thought the young man was married now? Or is this a previous GF?
Kids grow up at different rates. Something that happened four years ago should be forgiven, IMO. If he behaves the same way again, then that’s that – but I’d give the kid another chance. I doubt any of us were perfect at age 21.
It’s hard to read intent in a situation like this from afar, but I wonder if the young man just doesn’t have that much social intelligence. He may be a bit like a bull in a china shop in his interactions, and it puts people off, but not dramatically.
Am I right that your son’s GF thought he was rude too? When he didn’t come over to say hello in the restaurant?
In any case, if you allow your son and his friends to go to the weekend place, make it clear that they will be on their own for meals, and that they need to clean up and generally pull their weight. Feeling like a beleaguered host will only make you unhappy.
Maybe the guy sensed on his trip to your place that you didn’t warm up to him and because of that was hesitant to have a face to face with you.
Having raised threes boys and having a weekend retreat I have hosted dozens upon dozens of boys through the years. Some great. Some just awful house guests. I fed, them, made sure they had clean sheets and towels, picked up after them and when they were old enough probably brought the beer. The most interesting phenomenon was seeing which kids had mature social skills and which kids did not. Even more interesting were a few who “lacked” mature social skills at 17-18 who we’ve encountered out and about now that they are >25 who say to us We really appreciate everything you did for us when we were younger. We had such great times and we know wewere stupid sometimes and never told you how much we appreciated it. My feeling is unless the kid is a druggie, or you’re scared he’ll rob you blind or set your house on file… if he is a friend of your son let him mature before you pass judgement on him. He might surprise you down the line.
What has worked for us has been talking to our lads ahead of time when we know what behavior we didn’t like - to use an example, making scrambled eggs and leaving the kitchen for me to clean up. I can be many things, but a maid is NOT one of them. You make a mess, you clean it up. It’s how my kids were raised and it’s how most of their friends are naturally (or they ask politely, etc). One friend was not raised that way. I suspect from similar incidents that his family had a maid or his mom did it all. Originally I was fuming. After my lads talked to him and showed him how to do some basic tasks he fits in fine (mostly - enough that I don’t fume). Considering he’s here living with us for the summer, this is a very good thing. My lad likes him (and they work together - we’re the free lodging helping them both save money). It would never have worked out if the lad couldn’t adapt. (The first week I was ready to make them find an apartment - SEVERAL similar incidents - kitchen, bathroom, tracking in horse pasture mud, etc.) He could adapt. He just needed to have some gaps in his upbringing filled. Now he tries hard to be helpful. It’s a nice change.
You know what specifics irritate you. Have a nice conversation with your lad to see if he’s willing to help things change. I blamed my needs on “Old dog having a tough time learning new tricks” and it’s common sense (for me) that I’m NOT someone’s maid - esp not a grown college man. It made sense to my guys (plus, with their upbringing, they were a somewhat irritated too). Fixing things helped us all.
If your lad isn’t willing, can he explain to you why? I can’t fathom a good reason, but at that point you’d need to decide how willing you are to be irritated vs how much you want to accept your son’s friends. If my guys hadn’t helped I suspect I’d be spending a bit more time with my mom and letting them live here in the filth (only since I know they can’t afford an apartment - if they could - that would have been my first option).
As to your other comment, no, I didn’t mean it as a personal insult. It’s just my musing if I heard a story (as I did) about which way my mind would interpret it. I don’t always agree with the person telling the story. Sometimes I think they’re at fault with their response. This is true even with members of my own family and sometimes they tell me I didn’t handle things well - esp when I DID get MAD at the lad mentioned above after he forgot to flush - three times within 24 hours… I guess I should have been nicer, but… Creekland is human and we only have a one bathroom house. The good news is he’s learned to flush - and clean the sink when he’s done with it. 
I was raised that it’s rude to interrupt people out at restaurants. If they beckon you over or something, that’s different, but in general it’s rude. You don’t intrude uninvited on someone spending time with family or guests.
(On a side note only because it bothers me greatly, there is nothing unique about a pitbull’s grip.)
@conmama The way your son’s friend handled seeing his friend’s parents who had generously hosted him at the lake for a very nice weekend-just a dismissive sort of wave-would be considered VERY rude where I live. I personally would have considered that I still owed my friend’s generous parents more acknowledgment than that. It would be considered rude and a slight to do that to anyone other than a mere acquaintance when you see them out at a restaurant where I live though. I understand your pique. Imagine, in “To Kill a Mockingbird,” if Scout had just waved at Miss Maudie after Miss Maudie baked the Lane cake for her and Jem. Really, Maudie would have been legitimately affronted. That’s not the way they did it in Maycomb. Same here.
I do believe this would vary by social mores in different areas of the country however. You are in the best position to judge if this was intentional rudeness or a legitimate difference in social expectations because you know the young man in question. You are well within your rights to exclude anyone you want from your house but it may not be worth it, as others have pointed out, absent a safety issue.
I have zero interest in selecting who my kids can invite over or spend time with, just as long as something dangerous isn’t going on. I also don’t agree with the “my house, my rules” doctrine unless it is about something major, and that does not include a friend who may have had a different upbringing and maybe isn’t quite as polite as I would like. I would hate for my children to feel the house that they live in (or grew up in) isn’t also theirs!
Anyway, in this situation, I would (and have) offer the vacation house and tell my son that he needs to take care of everything, food, entertainment, etc, and he needs to leave the house clean and locked up.
@romanigypsyeyes and I are from the same area, and I completely agree with her view on not bothering people at dinner. I suppose it is probably a regional thing, but there is no way I would be upset at a wave in a restaurant.
To be honest, I would not expect a particular level of thankfulness from my kid’s buddy four years after he stayed at my cottage.
Lets give the kid a pass on the restaurant wave - we have no idea who he was with or what may be happening with him in that moment. We have a place where we host frequently and allow our kids to also host. We had one regular visitor who never lifted a finger to help or brought food to contribute. She wore out her welcome quickly. Others most often pitch in with dishes or cooking or bring some food and that is always appreciated. Unless someone was doing something illegal or immoral I tend to keep my friends close and my kids friends even closer 
I think you answered your own question. If you insist on not having this friend over without any reason other than his manners, this will likely alienate your son and make him choose other ways to entertain his friends without bringing them to your place.
Did he (or any of the other guests) write a thank you note after you hosted him? If not, I would consider him ungrateful/ rude/poorly trained. The restaurant wave? Not so bad. He might think it was rude to intrude on your meal. That’s my feeling. Unless it is your best friend or a close relative, I would consider waving to someone I saw at a restaurant “good enough”/the right thing to do–acknowledging them, but not interrupting. Maybe he had to be somewhere after that and would have been late if he’d started a conversation?
I’d let it go. It has been a long time.
I thought this was going to be one of those “Help my middle-schooler is running with the wrong crowd” threads!
Funny, but I live in the same general area as @kelsmom and @romanigypsyeyes, and I agree that I would never “bother” someone at dinner. Never! Strange how regional these differences can be.
I’ve definitely found that some kids have been taught better manners than others by their parents. Sometimes shyness can seem rude. Sometime (boys especially) don’t offer to help more when they are guests. And yes some people do annoy me, however the restaurant example seems like very small potatoes to me.
I will tell you a story - my youngest brother had an incredibly annoying girl friend who drifted around the house combing her hair. She was always late. She tended to be on the managing side. Eventually they got married. They had kids. I got to really like her. She still always seems to be brushing her hair. She’s still always late. But she’s an incredibly caring person. When she comes and visits us in NY we always have a great time. She was incredibly supportive each time my parents passed away. She’s now one of my favorite people - I’m glad I never said anything to my brother or kept her out of my house.
I understand how annoying a poor house guest can be. Both D and S had a BF/GF who H and I found difficult to be around. It was not single things but a cluster of self centered behavior. S was quite upset when we talked with him about how she never ever said thank you even after a great night out with us. She did learn but we were relieved when they broke up.
D was completely in love with a rude guy. H and I clenched our teeth but acted as if it was all good. She was older and talking to her would have alienated her, Eventually, she asked my true opinion and I told her. She broke up with him for a number of reasons.
I find very difficult to be with a person who grates me the wrong way for any length of time.
I would allow him to come. I also might be direct with him if there are concrete specific annoying things
that he does. The problem is that sometimes it is just a poor match. What I would try not to do is worry
about my initial reaction. Not liking someone is subjective.
“Part of me is just mad that DS doesn’t come to us to ask , but tells us as if we will just forget about it. I think I need to tell him that. So, what would you do? It just irritates me to have him there again, but I don’t want to alienate DS.”
It seems to me from the comment above that you are mad at both your son and his friend. Perhaps your son feels in the middle. He may feel your judgement of his friend is not warranted but he doesn’t want to make you angry and still wants to be friends with who he wants to.
Tell your son he must ASK if he can invite x, y and z friends to the property and that you will decide. That will likely alienate your son to some degree but maybe it will help you feel more in control. Had he asked if this friend could come would you have said yes?
If you really see a problem with his friend you may want to educate your son on how he should let his friend know what is expected. For instance, if you need the kids coming up to you whenever you see them to thank/chat/catch up tell your son to tell his friends that. Where I am from you wouldn’t intrude on someone else’s dinner unless you were waved over or your were really close friends or family. If I didn’t know them well I would definitely acknowledge them with a wave. Of course it is better to run up to the table and say " we know you are having dinner but we just wanted to say hi real quick and see how you all are?" Then if it was interrupting you would leave right away and if not carry on a bit more of conversation. Some people would feel intruded upon others not at all. I would, if I was your son, try to make the friend meet your expectations just so he can be around or invited back and I am sure your son would want that too.
Sometimes friends of your kids do not behave as you would want them to but deserve another chance. This may be that one time. If you get your son to ask to invite people to your place and have him educate his friends on the proper way to interact with you afterwards you may feel better. Good luck
Given that many people have stated that they believe interrupting someone’s dinner is really rude, and others have stated that merely giving a wave is really rude, it should be clear that there is no “right” stance, so the kid should really be given a complete pass on the restaurant incident.
Beyond that, it’s hard to say what the OP “should” do. She could allow his presence in her house, but that would be a long weekend for her. On the other hand, if her son values this friendship and she forbids his presence, it could backfire and the son might not be willing so spend as much time with them at the lake house.
When DS was younger, we often had his friends over and some came on vacation with us. Most were quite polite, and even more were charming. As he’s gotten older, one of the ways he’s decided to be independent is to keep his friends and family separate. I understand it, but it breaks my heart.
Be thankful that your son wants to be with you. Set the ground rules for visitors so that they are comfortable for you, but count your blessings that your son is not embarrassed by you and is happy to spend his free time with you and include you in his life. It’s not a given!
Interesting thread with the OP’s issues and the varying responses. I don’t know if the OP’s of an Asian background like me, but manners are a big thing in my culture. What the OP has experienced isn’t something I take it lightly, either. One of my DS2’s best friends is someone that I don’t approve of. Although a Korean-American born here like my DS2, his parents have brought him up in such manner that there’s not an iota of “Korean” about him except physically. When we see him, he just looks at you straight in the face with no attempt to bow like you’d as any Koreans or Korean-Americans are expected to, to show respect. He has absolutely no idea that just staring you in the face upon greeting an adult is a big insult. What’s worse is one time when he nodded at us with his chin. As the saying goes, a tree can be told by its fruit, and we just shake our heads and try to forget about it.
My wife and I have discussed this with our DS2 as a cultural lesson through example. He agrees with us as he has always on such issues. We’d tell him that, if he were to behave like that with others, he’d be besmirching the parents and the family’s honor, not just him. We also explain to him that when he himself becomes a parent one day, he should always raise his kids such that his kids would be loved even by the strangers and not just by him and his wife as the parents. That rude young man that the OP described could have been treated to lots of free drinks, food and entertainments for years by the OP’s generosity and love. Instead, not knowing what good mannerism is, and even more importantly, not bothering to show a simple gesture of respect for all the love and generosity he had been showered with in the past, he’s managed to antagonize.
The solution for my family with regard to my DS2’s friend: we decide to recognize that young man’s core to be a good person. Being assured that our son fully recognizes what such mannerism of his friend means in our cultural context, we were okay with our son’s own choice to hang with him or not. His friend has also been exhibiting extreme self-centered behavior, as well. Our son recognizes that in his friend, too, and as long as he knows when he’s being “used” or not by his friend and make his own decision as to how to deal with such situations, we’re okay with their continuing friendship.