Except there possibly is a part of Sam that remembers. For all the pain that he went through with the return of those nearly two hundred years in the Cage, there is definitely a memory in there of a bright, shining light that at least tried.

And for everything that they've gone through, Sam has never blamed Castiel for not being able to get him out.

He doesn't try to stop Castiel from crying. Doesn't tell him that it'll be all right. It's all platitudes right now. What he does do is tell Castiel that he's doing well, that it's only a little further and then they'll be home. Little bits of praise to help Castiel through the ride.

Once they arrive at the bunker, Sam pats Castiel's hand. "Take hold of Dean again, all right? I'll only be a few moments around the car, then I can help you out on your side."