[He'd only just begun to grasp the existence of other worlds, and he didn't know enough about his own to really tell them apart unless something existed in them that he was certain was not in his own. He tended to assume everyone from Earth was from the same Earth, unless there was a blatant contradiction somewhere.]

Yes. Don't ask how, but I believe I will still be there to see it. Tell me what you call your home and how you define your time. I cannot bring more tangible aid, but some of the things I learned from my own life among the earliest men may be of use to your world. I wish to at least try to help.

[Yes, he just admitted he's ancient. And immortal. Actually, he wouldn't be there for it even if their worlds were the same, because he is, in fact, going to die, but there's no way for him to know that.]