Have you told mom about his behavior?
I think you need to ask her to have someone else pick up kiddo one evening, then come over for a meeting. You need to tell her gently but directly that whatever is going on at home is really affecting dcb. You love the little guy, you know she loves him, wants what's best. She needs a wake up call!
Seriously, let me call her. I'll give her an earful of what it's like to grow up like that! Mom gets wacked, leaves, and then comes right back.
nice...
