Don't know what to do.

Hi there My father has struggled with alcoholism my whole life and began using drugs as of 4 years ago. He has always been depressed about himself and has no self esteem to speak of. He suffers from bi polar on which he is prescribed paxil. Anyway I had my suspisions of him using drugs quite a while ago but he only admitted it to me just over a year and a half ago... Instinctively I instantly tried to get him into treatment but he constantly avoids the topic and/or procrastinates and sometimes tells me false stories that he has arranged to go into treatment within the following weeks and never follows through. He has asked me to keep this lifestyle private from my grandparents (his parents) because he wants to have his life in the right direction so his parents dont think less of him "than they already do", as he puts it. Him and I recently got into an argument over him procratinating going to treatment and I finally admitted my dark secret I have been keeping from my family. I was at first relieved that I told them because they seemed to agree with my views on getting him to treatment asap. The new barrier I am facing is that my grandparents wont accept that my dad manipulates them into thinking he has a good paying job, he is sober from alcohol (which is very untrue) and going to school to become certified. I know it is untrue for the fact that all the times my dad says he is going away for work... He is telling me he is going for treatment but then I find out he has not even done that but decided to go on a binge instead since he is uncontactable each time it happens. I am afraid my grandparents dont understand the seriousness of his situation and how far downhill my dad realy has gone. He used to own a hair salon and graduated with honorable awards from hair school. He is an extremely talented man musical, poetically, and in virtually every hobby or interest he has ever shown a liking for. He ended up getting into a alcoholic relationship which caused the initial failing of his salon. Sales and clientel both decreased and then he met another woman. She ended up introducing him to cocaine and later herion. He ended up selling his salon and is still in debt for that. He recently became homeless as of yesterday evening. After my talk with my grandparents they told me to stop focusing on my dad and focus on my dreams of getting enrolled in school. They told me to let them deal with their son. Easier said than done... As my dad is constantly getting mad at me for not being in his life more and blames my absense for his addiction. I know he does not mean these hurtful words as his addiction is a complex situation. The thing is it is absolutely impossible to not let this obtain all my focus when my grandparents call me everytime they cant get a hold of my dad and expect me to go find his whereabouts. Which he does go mia on a regular basis. So i really dont see how i can think to concentrate on schooling when I am constantly worrying about my father. My grandparents have said they will stop supplying him with money as they have been, oblivious to his drug addiction. But they are unsure how to get him into treatment without him losing his job, and fear for him becoming more depressed. So my dad is currently uncontactable again and has no address to reach him at. I dont know what to do to get him the help he deserves and needs. I lost my mom 7 years ago to drug addiction and was not even living with her nor in contact when she was an addict. I had no control over helping her, I do havexthe chance to help my dad and I dont want this chance to slip away for I fear everyday is his last at this moment. I guess thats why I cant seem to focus on my life right now. Any suggestions would be muchly appreciated as I have tried all that I can think of trying. Thank you very much for taking the time to read my story. Trina