What if Supernatural ended with Dean in a psychiatric ward, and he’d been there for years. Sam died in the fire with Mary and he watched his house burn away, with his mother and brother inside of it, and it was mentally traumatizing. So he made of a world of monsters when he was young, and it grew darker as he grew older, and eventually John couldn’t take it anymore. His psychiatrist, Dr. Cas, gets a bit concerned on the times which Dean refers to him as Castiel, but at the same time he understands. He talks about angels, he said his mother used to say they were watching over him.