> ADHD doesn't work like that. If anything, it means that he'd pay even more attention to the fighting going on, as being ADHD means you usually foocus on a billion things that are happening all around.

Actually, there are different types of ADHD, I have a type which makes me zone out, but I'm still really impulsive. Aaron's is the type that makes him really impulsive.
Plus, He could have Jet Lag.