My son's drug of choice is meth- he's been in and out of active use for several years. I know that someone else cannot force an addict to get clean - threats, guilt, anger, other types of manipulation don't work. Also, while expressing your anger toward your dad might make you feel better, he's already in a hell of his own making so whatever you say or do probably won't make that much of a difference. I am SO sorry for what you are going through. You need to do what is best for you- living with your dad part of the time because you don't want to abandon him obviously is causing you a lot of physical and mental stress.