A book that helped me (and others) immensely: Boundaries by Townsend and Cloud.

The book that saved my life: THe Verbally Abusive Relationship by Patricia Evans.

abusive people are angry and miserable and need a constant supply of putting others down and hearing them explain themselves. They are emotional vampires. You can stop that. Let them know you will not have a conversation unless they speak to you with respect. The usual reply will be more anger and denial of their abuse. That is THEIR stuff, and you can hang up or walk away. We all need boundaries. Abusers don't like it when we call them on their behavior (just like a spoiled child).

You wouldn't let anyone throw rocks at you but that is what abusers are doing. It is okay to show compassion, but to not allow him/anyone to violate you.