Castiel's gaze intensified. "I am your friend. The last time I saw you we were with the Prophet Chuck--" only Cas could keep a straight face saying 'the Prophet Chuck' all caps included, "--and then I took you to Sam at the convent in Maryland. Do you remember?"
Perhaps Dean had fallen and hit his head. Perhaps the loss of Sam had unhinged him entirely, and that was why he was in some motel burning to death on cheap hotel fabrics. Perhaps God had sent Castiel here to save him. Castiel's purpose had always been to preserve Dean Winchester. Yes. That must be it. "I must have been protected to save you," Castiel said, thinking out loud to himself and again looking around himself. "But I do not know this place."