What if Supernatural is just a story being written by a lonely writer who lives across the street from these two brothers? No one ever really spoke to him, or bothered to ask if he was okay, but one day his car broke down and the older brother came out and helped him fix it. The next day the younger brother came over to see if he could use his computer to take an online test for class and they end up talking about Stanford. Suddenly, he has friends, and they are his heroes, so he sits down and writes amazing adventures where the brothers are the heroes, and they save people. Bad things happen, but family is the most important thing.
Then, on a whim, he writes himself into the story. He changes his mind later, and kills the character based on himself, but neither brother will let him stay out of their lives for long. If he hides away, they come and find him. If he tries to cut them out, they forgive him.
One day he comes home to find the elder brother on his computer, reading his stories, and all he can think of is how he wrote his own character, staring longingly at this man, wistful, but ever distant.
“So Dean…that’s me, right?”
And he nods, ever so slightly. “I’m sorry.”
“Sorry for what?”
And then the elder brother grins. “What are you talking about? Cas is my favorite character.”