I know a man in his late seventies. Can work outside in the heat for hours without flinching, has no major health issues and he never touched alcohol once in his whole live. I have a hard time thinking that his abstinence is unrelated to his longevity. On the other hand, some people's bodies seem to be able to handle it.

I'm sorry to hear about your friend. I'm the type who thinks that a principled life needs to have some exceptions - this is a good example.