I think it's worth noting that alcoholism isn't identical to using or even abusing alcohol, although there's obviously a large overlap. Movie Tony undoubtedly drinks heavily, but I'm not sure there's evidence he's an alcoholic - when he's working on the Iron Man Mk II, for instance, he stays in the lab for days and doesn't drink anything, and drinking rarely interferes with his life - in Iron Man II his drunken bad behaviour is more connected with his imminent death than the booze.