Pretty sure he'd be ok with natural causes with dying of time. I mean characters can't live forever, they gotta die sometime....unless of course your a DC character. Marvel was ok, they killed off a majority of their characters.
Marvel is even worse than DC, though. As far as killing off characters that then come back to life. Even Magik came back after dying of the Legacy virus.
Not to mention Marvel snatching the "multiverse" concept from DC, now. And pretty much every character that Stan Lee didn't create is a carbon copy clone of a character in DC, only with minor differences. lol