I think he's still in there, he just got very very confused. I mean he was betrayed by that many women (8 according to comic-canon!) left to die on a desert island, bullied by his father ALL his life, the Julian-thing, poisoned, oh yeah: lost his hair, brain-fried and had to slowly watch as Clark fell away from him and he didn't even really know why. He just needs a cuddle. And Clark (that is, the one in my head) feels so guilty about giving up on him and not saving him from himself...