I agreed with Granny Fran. By the end of the day he is just too exhausted to care any more.
Is he eating well? Maybe a protein snack after school and one in the evening will help. My son runs till he is completely on empty. I keep lots of food around for him and helps with the moods.
Ds always seems to "act more ADHD" at night. He is not currently taking meds, so it isn't rebound, although that was an issue when he took Vyvanse. I could tell when it was worn off almost to the minute! But why is he acting so crazy at night now?
He's almost 15, btw.
It could simply be that he has to struggle so hard to keep his act together during the day that by night, when he is home and safe, he can relax his guard.