He was a decent human being, from all I know, and was one of the few Harry Potter actors who fit their roles perfectly.

Why do they die so young? Alan Rickman wasn't that old either, and from what I know, neither lived the kind of life that might be blamed for famous actors dying young (alcohol and other drugs and excessive partying and all that).

Oh Robbie had a big drink problem on and off. Iron constitution when young, could put it away by the gallon. And relatedly very overweight. It's not a surprise that he'd not make the oldest of bones since his heart was probably working overtime much of his life. But it's so sad.