Shana,
It is hard at your age to have to listen to your parents and to hear that your father denies his alcoholism--it must make you feel helpless, angry, and scared---Sadly enough, you can't do anything to help him admit his problem. I don't know whether you've tried to talk with him about how his drinking affects you? Maybe that would at least give him another reason to think about admitting his problem. It is very hard to understand why someone can't do this. It is a disease, as you know, and I think you are doing well by focusing on your homework and yourself.
Maybe others will have some wise words for you.
Best wishes and prayers.