“He was lost, Cas. Our last hunt, he almost didn’t make it back and said he saw Billie.”
“He saw Billie?” Castiel parroted. They were both still in the war room in the bunker, the aftermath of recent events still fresh and new in their minds as Sam recounted what happened while Castiel had been “away.”
“Yeah, and it wasn’t great.” Sam bit his lip. “Cas, When Mom disappeared…when you died. I think it broke him to a point where he couldn’t come back from it and deal with his grief. More than one night he’s had nightmares where I’d have to get him out and it’s always your name that’d he’d scream.”
“Grief is a complex emotion that is difficult to understand. The both of you have suffered with it greatly, but I have passed before.” Castiel paused, cognizant the statement should make no sense to anyone else except for the three of them. “He had been in grief then but had managed to find a way out. What made this time different?”
“I saw your wings, Cas.” A voice interrupted them from the threshold of the war room.
It clicked in Castiel’s head then. Understandable. "Dean.”