I really dont know what to do

my uncle,will call him F, is gay and has hepatitis c.also he is addicted to some serious shit. I like my uncle,it took me a while to get used to the fact that he gay,and i dont wanna see him wind up dead. I know he prolly wont live long from the hepatitis c but i dont understand why he keeps goin back to drugs. It seems like he relapses he'll be clean for so long then go and get back on the same ole shit. Even though he gay he my uncle and he pretty chill so is there anythin i can do for em. btw he has done some fucked up shit like stealin money but i blame it on drugs. i need advice on wat to say or do. I wish i knew where he was he lost his job i think.