Another vote for – “he’s fine”.
Sounds like great attire for an outdoor summer wedding. (I love bow ties. 
) It is basically a more individual version of the absolutely safest thing to wear: the classic navy blazer with grey pants and a dress shirt and tie (summer weight, of course).
Bow ties are cool!
is it a clip on tie?
Thanks for the feedback, everyone!
Wedding is at 4 PM. Small, college town setting. Rather sophisticated/affluent bride and groom. No to the clip-on! He informs he can even tie it himself! (“Mom you can learn how to do anything if you google it!”) His dad taught him how to tie a regular tie when he was quite young~
I like his outfit better than the boring suit option.
This sounds appropriate to me. What they don’t want to see is anyone in jeans and flip flops or shirtsleeves, unpressed cargo pants and so on…
I’m wondering, is “cocktail attire” also code for “fancier wedding gift”?
No
Its just code for grownups please.
Discussion at dinner tonight with friends of the bride’s parents: cocktail attire to them means suit. But they are our generation (parents).
To me, any nice jacket, non-jeans slacks, classic-type clothes would qualify. The OP’s certainly would fit that criteria well.
I think he will be fine with the suggested jacket. I definitely think there are ‘generational’ rights and wrongs when it comes to fashion!
I think cocktail attire implies a jacket for a man, though a linen unstructured could be fine (on the right guy).
I know when my niece got married she put cocktail attire on the invitation as she didn’t want the young people to come in jeans or khakis. Most everyone over the age of 40 were wearing suits or cocktail dresses. Even the younger crowd had on a sport coat and tie at the minimum.
Now I am going to sound like my mother, cocktail to me is dressy, below that might be dressy casual!
Reporting back: that was one helluva good time last night! Older guys were in suits and ties. Younger generation were about 1/3 in suits, 1/3 in slacks and jackets and 1/3 in button down shirts and slacks. Of the younger crowd there was a mixture of traditional ties, bow ties and no ties. So your don will be just fine.
I’m waiting for pictures and more details, Jym. I doubt I am alone.
Awesome, jym! I bet some of those jackets came off when the dancing started! 
It got cold so many jackets stayed on. But it was a great time. Thanks all.