Pity is condescending and not the same as compassion, regardless of what its denotation is. You may want to help him understand himself better, but that isn't your place anymore. He doesn't value your input. He is not going to hear anything you say to him.
The best way to get away from him for your own sanity is gray rock. No emotion. No supply. Don't feed the machine. They really don't like it when you don't fight back. Makes it much harder to hate you and blame you. In time you'll feel a certain quiet power in restraint.
Your truth and his truth are two separate things. There is no absolute truth. You don't have the truth on your side any more than he does and you don't want to be self-righteous.
Let him go with as little energy as possible. Remember the whole what we resist persists thing.
