Dude break up with her and have the police there as witness, hell i’d even press charges against the dad for knocking you around the first time.

This is not the middle ages, you can’t be forced into a relationship by someones parents.

I am afraid for you, don’t let yourself be pushed around like this, I wish I could lift you up and give you courage to get out if this shitty situation.

Sounds like Dad and gf need to be in jail, make sure the police are there to do that. If you’re not sure how to get them there the truth works perfectly “Can I get a unit to my house? I’m breaking up with my insane girlfriend and her father has assaulted me and threatened me with a gun over it and I fear for my life, please send someone to help.”