I also agree that with the others. He’s lost his dad recently. He’s facing a big transition in his life, going off to college. These are stressful. He’s about to say goodbye to several of his friends from high school. His whole life is being turned upside down. Who wouldn’t be reactive? It’s especially hard because you’re probably worn out too. He’s also probably bigger than you now! This happens with boys.
But I think the main thing that I would tell my own child is the one thing that I would want to hear every single day if I was going through a big, scary transition: which is: “You’re going to be okay. You are okay already. I’m not worried at all.” And hug him every day really tight before he goes off to school, if he lets you. Sometimes it helps to know that your parent is a Rock of Gibraltar and has faith in you and your ability to make decisions, no matter what you’re going through and no matter how crappily you made a decision just five minutes earlier.
If he yells at you, even if it’s unfair, see if you can keep quiet and just listen. Plant your feet. Hold your tongue and just listen. I would bet that he would be grateful to know that you are not judgmental if he burns off some anger. He would be glad to have someone just listen, to whatever is going on. You can always do some correcting or skillbuilding and editing several hours or even days after the anger passes. He knows when he’s done something he shouldn’t. He’s probably just as upset about his behavior as you. And will probably self-correct and apologize on his own in good time.
Then each day I would find two or three things that he did well that day, highlight those, and ignore the things he did wrong. He will get back on track. I’m sure of it.