After everything we survived together, I watched the man I love die. There's no normal after that.
Which means neither Sam nor Dean has been "normal" since All Hell Breaks Loose and Mystery Spot, respectively.


I believe Billie may have been taking a page from her master, Death. He built the "Great Wall of Sam" even after Dean failed his test because he wanted the boys to "keep digging." Billie called Dean on his BS that only Sam can save the world. Maybe she wouldn't have swapped brothers, even if Sam knew how to stop the Darkness. But, Billie knew he wasn't, and she told Dean. IMO, she also knew that as long as Sam was alive, Dean would fight to live; and they would keep digging.


For me, it was a bi-bro show because it showed how far each of the brothers were willing to go to save the other.
While Dean had more character development; Sam demonstrated (once again) that he was determined not to die as long as Dean needed him. Sam could tell from the state of the cabin there hadn't been a fight, and that Dean left of his own free will. If Corbin hadn't been bitten, I think Sam would have simply patched himself up as best he could and waited for Dean to come back. It was the threat Corbin posed to Dean that got him out of the cabin and to the hospital. As you noted, he collapsed as soon as Dean said he was okay.


*leaves critic mode & enters fangirl mode*

O. M. G. SHOW! I haz ALLLLLLL the feelz! And the pretty! Hurt Pretty, Despair Pretty. ALLLLL the pretties. *iz ded*