Oh dear! That is awful that the school is not helping you! Could you stay with your close friend a while longer? Could your friend's parents help you find a way to get your needs across?
I know the idea of calling the police and possibly having your father go to prison is frightening. Yet, that might be the only thing that could actually save him. He would have the opportunity to get clean and sober there. Honestly, in my very humble opinion, you would be showing how much you love your dad if you can call the police and let the consequences fall where they may.
You deserve to live a safe and healthy life. And sometimes that means we can't continue to protect those we love from dealing with consequences.
If it has any significance to you at all - I am currently dealing with the knowledge that one of my sons might end up going to prison. We have invested years covering/protecting/spending $ to keep him from that consequence - but he hasn't changed and we now realize that time in prison could actually be what will save him.
Big Hugs to you. This isn't easy, especially at your age. Keep posting - we are here to support you.