User blog comment:ImperiexSeed/Castiel's shifting of Sam's mental problems made no sense!/@comment-4003779-20120402012732/@comment-3481504-20120402013452

That's good, so it's not confusing, cause I honestly thought I'd be the only one who caught that, guess not.

I don't know, but Death did say, "can't erase Sam's hell", which is kinda what Cas did, in a manner of speaking. Also, Cas, Crowley, and even Balthazar prefaced the importance of it, take the conversation in "Caged Heat" for example.