He's put you in an incredibly tough position, and of course it is not just this latest episode...

I wish you strength, fortitude and the help of friends that you need to get out. It won't be easy but it will be a relief when it is finally over. It doesn't seem like he is occupying to much space in your head, which is the way these kind of people tend to control those around them, like the parasite in humans that comes from cats... except stronger.

If it were me I'd probably ditch talking to his dad in favour of breaking all ties and communication and try to make this as painless as possible for you.