Chapter 60.
They heard Cas come down the stairs and then he appeared in the doorway. He looked at Dean, who immediately saw the worry and the guilt and felt bad about both.
"I'm sorry I disturbed you, Cas." he said.
"I'm sorry to interrupt." said Cas, "I know you and Sarah are making progress and I don't want to interfere, but it felt like you were shouting for help. I couldn't ignore it."
"Come in, Castiel." said Sarah.
He did. He sat to Dean's left. "It's getting late. Well, actually, it's getting very early and although I'm glad to know you are talking about that stuff, I think you need some rest."
"I'm not too tired." said Dean, "Sam needs sleep a lot more."
"Sam is asleep. I checked on him a while ago." said Cas, "I think you should sleep now, Dean. You look terrible. You need a few hours' sleep."
"Thanks." said Dean, "I'm more concerned with what you need."
"What do you mean?" said Cas.
"You're going through this with me. I'm guessing abandoning it for sleep will give you some peace, but what if my dreams are bad? What if they're bad enough to drag you into my nightmares? I just need to know what's best for you, sleep and risk dreams, sleep without dreams due to your angelic powers or stay awake and work through this."
"I don't matter, Dean." said Cas.
"You matter to me." said Dean, "You could zap me and stop all dreams for the night."
"Zap you?" said Sarah.
Cas turned to her. "What you call a sleep blessing, he refers to as zapping."
"Wait," said Dean, "You zap her?"
"Sometimes. Sarah has never had an issue with it. She trusts me."
"I trust you." said Dean.
Cas raised an eyebrow, but declined to comment further.
Sarah spoke. "Could I put in a vote for letting dreams play out as they will? I don't want either of you to suffer, but dreams can be deeply healing things and I feel as if Dean is ready to start healing these wounds."
"What do you think, Cas?" said Dean.
"I think Sarah knows what she's talking about." said Cas.
"But can you handle my dreams?"
"Better than you can, I suspect." said Cas, "And this thing between us, it might actually be useful for this. I've always been able to go into dreams, but now, we have a connection that may increase the effectiveness of my intervention."
"Or could drag you in so deep that you lose your mind." said Dean.
"Also a possibility." Cas admitted.
"Not one I want to risk." said Dean.
"My risk, my choice." said Cas.
"We need you to fight Michael. Cold logic says we can't afford to lose you as an effective fighting force."
"At best, I will draw his fire for a moment. I never had a chance of fighting Michael." said Cas, "Maybe, in the end, freeing you from some of your demons will prove to be a far more useful contribution to the larger fight. Cold logic says I am a lot more expendable than any Winchester."
"Then screw cold logic." said Dean, "I am not risking you."
"You're assuming I can't cope with your dreams. I think I can. I can also bring Sarah into them."
"You know what my Hell was like. You want to let her see it?" said Dean.
"She's stronger than she looks and she has shared more people's Hells than I have."
"Dean, we need to try this." said Sarah.
Dean knew there was something happening in his head, something that might lead to healing or to insanity. His best chance of the former was to let Cas and Sarah help, but to do so, he had to ignore the urgings of his mind not to put good people at risk for a worthless one.
He heard a whisper in his head, an unintentional plea from his best friend. "Trust me. I love you."
"Okay." he said, "But if things get bad, you two get out."
"We will." said Sarah.
"Where shall we do this?" said Cas.
"Not upstairs. Sam would wake up." said Dean.
"My room." said Cas, "It's not like I need the bed."
They went upstairs together. Dean lay on the bed and Cas gently put him to sleep.