I agree that he’s probably grappling with the diagnosis and what it means. I’d let him know you’re there to talk about it when he’s ready, and remind him that he’s the same person today that he was a week ago before diagnosis, now he just has a name for the struggles.
I’d also give serious consideration to the question of wether he’ll truly be ready for college/able to succeed this fall. Most neurotypicals struggle to hold it together as freshman in college. With lagging executive functioning skills of ADHD, it’s 10 times harder. I’m not saying he can’t do it and succeed this fall, I’m saying spend a lot of time thinking about it, talking about it, and being honest with yourselves about it. If he goes forward as planned this fall, make sure he has a plan in place and lots of support, and work on establishing tools and strategies to help him succeed before college starts.
ADDitude Community Moderator, Parenting ADHD Coach & Author, Mom to teen w/ ADHD, LDs, and autism