Time existed in Purgatory, but the only time that ever showed was the endless nights. It was always dark, and it was always cold. Dean was homesick, and so painfully human, and so very, very afraid, meaning sleep wouldn't come even when he and Benny had found refuge safe enough to have it in. He split Purgatory in half looking for his angel, and when he found him, found that one piece of home he had really needed, Dean managed to get in an hour or two as long as Castiel was right there beside him.
One day, I'll get good enough to do my Purgatory Destiel headcanons justice. I learned a new coloring technique-- er, remembered a friend using it, at least, and I think it's really helped me. I mean, not a lot, I still have a long way to go, but I'm making a little progress at least.
Dean, Castiel (C) Supernatural