Originally Posted by
LexieCat 
And yes, he was acting like a jerk. Engaging with him isn't the best strategy. This is where detachment comes in, as in walking away from the conversation.
I second Lexie's suggestion. In detaching, we try not to argue nor justify. He was trying to engage you. You were on the right track when you were telling him to do what he wanted/needed to do. Don't engage him when he is quacking.
I remember someone posting here that she used lots neutral responses: Mmm, maybe, okay, sure.
Detaching and avoiding engagement is not easy to do and takes some practice and probably even more so personal growth.
Hang tough PC and let us know how you get on!!