My best friends dad is a drunk druggie.?

That's a really tough situation. You're right, telling them to go to rehab is pointless, because until they admit they have a problem, or want to quit, they won't. Calling the police is a double edged sword. If you were to do that, he would most likely only be locked up for a couple days at most, and he could possibly lose his job, and feel betrayed by you and his family. I guess the best advice I have for you would be to have a bunch of family members sit him down, tell him how they all truly feel, and try to get him to admit he has a problem... I know it's easier said than done. Unfortunately, sometimes people that have this much of a problem only realize this after it's too late. Good luck to you, and I hope your situation improves soon.