From my story, Talasam:
Sam let go of Matty and sat back in his chair with eyes closed. “I don’t know exactly what happened to them after they escaped. They had a few run ins with the Tribes, but when Mina killed a civilian they had to separate. They knew there’d be no hiding from that. It was nearly a year later that Rick and I found Matty in that stinking sewer. Thanks to Dzubenko’s brain damage, he couldn’t hold down a job. He was under a hundred pounds before we cut off his food supply and sick with so many infections… if it weren’t for that werewolf constitution he’d be dead.”
Dean nodded, unable to speak.
Why didn’t you tell me any of this? Am I so hard to talk to? Don’t you trust me?
“Getting him to trust us… I let Rick handle that. I swear, the man isn’t capable of lying. Matty spent four or five days verbally and mentally abusing him, but eventually, Matty’s intellect overrode his suspicion. Rick’s too open, too earnest to be a fraud. Once Matty realized that, I swooped in and told him about me and Nick. And that was that. As soon as Matty had his strength back, we went after Mina.” Sam grabbed Matty’s leg. “Do you have anything to add, son?”
Dean found himself studying Matty’s closed eyelids looking for some movement, but that thin, olive face might as well have been frozen.
Sam stood up and stretched. “I’m going to interrupt whatever Mina and Rick are doing and drag them back here.” Sam looked over at the bed. “Not even that gets a twitch out you?”
Dean smiled. “He’s been surprisingly cool about them… doing whatever it is they’ve been doing.”
Sam barked out a laugh. “Nothing surprising about it. He realized the two of them together means they’re preoccupied with each other, rather than getting him out of his room. Remember, the commands Dzubenko used to alter his brain make him want to be locked away. Matty’s worst enemy is his own mind.”
As Sam left the room, Dean’s stomach flipped again. He tried to banish the thoughts that fell into place, but they kept coming back.
Is that why we never go to my place? Or leave the house? Just how far are you willing to go to stay in your room, Matty?