Though, is he? He is a trickster and manipulator after all. Maybe he's planning something? What exactly was up in the first episode, inviting his younger self to meet up with the group right after his death? If he really did invite himself, that is. He doesn't find out about his death until Amy tells him in episode 6. It's not mentioned again until the Justice people in LKH mention it and the Doctor sees the date of death at the end of the episode. He's getting the info in bits and pieces and we don't really see him going along with it, other than the picnic and invites in the first episode. I'm sure he's planning something as he keeps getting tidbits of information. I don't think he's going along with it, as much as he keeps trying to get more information about it.