Well, since there's nothing you can do about it, I would suggest that you avoid him as much as possible. I'm assuming there will be several people there, so I can't imagine him trying to do anything physical. He might, however, attempt to engage you to try to make it look like you are argumentative. It's better to have to deal with him in public than inside your home.
I'm sorry he just keeps pushing and pushing. It would be nice if he just fell over a cliff somewhere.
