It's good that you can see the difference between understanding him and making excuses for him. There is probably a good amount of "monkey see, monkey do" going on with AJ. He needs to handle his bad feelings without making other people responsible for them, which is what he does when he blows up like that when he feels others make him feel bad for procrastinating. Letting him stand on his own sounds like a good idea. sometimes even when stuff like with his father is not in one's background, living together with a parent can be very trying and difficult. I love my mother, but she is very, very triggering for me and we can have terrible fights. We do best living at a distance and visiting. That way we can take responsibility for ourselves and not give into trying to manage each other, or get involved in each other's emotional life. (not saying this is what is going on with you and AJ)
Take good care of yourself, Radio. HUGGGGS