If I didn't make it obvious enough from my post, atheists don't rule out the possibility of God, they just don't believe because there's no reason to.

He was both an agnostic and an atheist; he just didn't understand the terminology. If I asked you if my wallet was in my pocket, you would say "I don't know." and that doesn't mean you think that there's no possibility that my wallet is in my pocket, but there'd be no reason for you to believe it was, because you haven't seen my pockets.

If you look at his story of the dragon in his garage, it's obvious that he was an atheist.

Again, an atheist does not "believe there is no god" or rule out the possibility of a god, they just don't currently believe because they haven't been given a reason to.