Pete was not human

Just watched the movie and had massive impression that Pete was not quite human. He practically had infinite stamina without any hint of fatigue as he hangs around the group preaching his optimism and mutual aid while saving Ray constantly. Even in the final stretch. He never seems to be interested in the prize at all.

I always had impression Pete is simply an angel of Death aiding Ray to help stir him away from his suicidal mission.

When that failed, the only last thing left is to fulfil Ray’s wish.