I jut can't take it anymore!!!?

My dad is a drunk. He goes out partying every single night, and we don't even know where. And when he's home all he does is yell and verbally abuse (sometimes physically/sexually) us. I'm sick of this, and my mom does nothing to protect us, even if she is scared i'm her daughter and she should protect me from him. I can't even tell when he's drunk anymore. The other day, I was driving on the highway with him and I could kind of tell he was drunk because he was swirving all over the place and he kept texting too. I was so scared! I can not take this anymore. I'm only 15 so I can't move out. I thought about just telling the cops, but then I thought about his side of the family, and how they would hate me If I did anything. And my whole family would be torn apart, even though it already is. But still, I hate making people sad even if it makes me sad. I just really don't know what to do. I'm stuck. advice. I feel like I'm so powerless and that this is normal, so I should just leave it. i dont knoww.....