If the JWs DF'd him, it would be doing the rest of the congregation a favor, but if he is abusing your mom, she should report it and you (and elders if they give a damn) should help her to get in a safe place. Your dad is not safe to your mom or any person. He hurts animals, his wife and he'd hurt you too.
Honestly, if the congregation helped your mom in this, I'd be willing to risk having some warm and fuzzies directed their way. I don't WANT to loathe everything about the org. I am happy to see them do something right. I am happy when true goodness prevails over WT interests.
Aid and abet them to do the right thing for your mom and innocent animals everywhere.