I recently read this book.
https://www.amazon.com/Only-Mother-Could-Love-Him/dp/0340838922 and it was interesting in that a young adult describes what his childhood was like with adhd and what was going through his head. Maybe it would give you some insight? I dont think people realize how adhd can reallly be a big problem because of the executive functioning aspect of it. It's not really much different than any other learning disability. so unless you have reason to believe he has dyslexia, dyscalculia, etc. you can probably assume some of it is ADHD and the poor executive functioning that goes along with it (problems with focus, initiation, organization, planning, etc), some of it is negative thought patterns based on past experiences, some of it is just plain lazy or obnoxious behavior. There doesn't have to be just one explanation. Research ways to get him organized, scaffold his work, and help improve executive functioning skills.
