Sounds like you don't have control of your house. Sounds like its not your house (your dad's)? Hard to say what to do cause you gotta keep it copasetic at the house and parents don't like drama. Hopefully your dad understands personal space issues and legitimate desire to avoid crimes with steep sentences?
There's nothing wrong with calling the police. They can't protect you in real time (usually), but if **** goes down they mop it up. And paper trails are a good way to insulate yourself from legal action. I say you don't narc on friends that turn to enemies. Keep your enemies secrets so they'll keep yours. Even then its not about honor, just self-interest. Also, if you make a promise to keep a secret then do not betray that. When someone constitutes a legitmate threat to your person and you have not offered such a haven, all bets are off. My code is doing the right thing, which may involve the police or may not. My code is also exercising discretion and not using the police when I believe that will inflame a situation or if it might cause unnecessary harm to that inidividual through over reaction by the police.
But I carry an x26c taser and no one comes inside this space. Good luck to you sir.