Oh god, what a great line. It pointed out that Dean was not only completely at a loss to what to do but that he was so human that none of this stuff never really meant anything to him. This isn't even his fight, dammit. It's like how I said in my post that 40 years in hell isn't something you can really conceive of without experiencing it. Dean knows enough to know what he doesn't know. Lucifer coming back sounds really bad, but it's like so bad that he doesn't even have a point of reference. If he's going to be, you know, TOTALLY RESPONSIBLE FOR STOPPING AND STARTING THE WHOLE THING he ought to have more of a clue, but at this point he feels powerless and probably pretty fucking stupid and he's just going to let Castiel know it because wtf, how much worse could he look?

It's probably a familiar feeling for Dean too. Can't you imagine him as a kid struggling to understand what exactly his Dad is fighting and what he needs him to do? But there was probably so many times when little!Dean was asking just that question in his head--or even asking it aloud and not getting an answer. This is all beyond me, what does it even mean? And probably back then the best he could do was: It means somebody might hurt Sammy and I have to protect him.