Written before 10x09
Dean can see it in his eyes when he looks at him.
You're right, okay? I see a light at the end of this tunnel.
Sam doesn't have a clue.
Sam doesn't have a clue what to do, or how to fix this, much as he wishes he did. Every time Dean looks at him he can see the determination, the desperation growing in Sam's eyes.
And if you come with me I can take you to it.
Dean knows how much Sam wants to save him. It's why Sam's been so pushy, and protective, and fierce. Prodding Dean, poking him, driving them both into research. He keeps promising Dean they're going to fix it, they're going to make it right. "Just trust me, Dean. We'll fix it."
I believe in you, Dean.
But that's just the thing.
Cole, once you touch that darkness it never goes away.
Dean did trust Sam once. Sam begged him, please, please believe in me, and Dean had. He'd gripped his Peter Pan of a brother, and dragged them both straight on 'til morning. Believing in Sam, believing Sam could really fix him, bring them both to this "light."
Now the truth is-
But all Dean got out of Never Land was the one thing he never wanted to see: a half dead brother.
We got ourselves a problem. It's Sam. He's um… they say he's dying.
And then a little brother who hated him. And things just kept getting darker from there, 'til now…
-I'm past saving.
Dean could see it in Sam's eyes, again. The same plea. Believe in me, Dean. "Let me save you." Trust me. Problem was, Dean had trusted Sam. He had believed Sam could save him. He'd followed Sam, done what Sam asked, pushed them both through the trials, and still, Dean had ended up with the short end of the stick. It wasn't Sam's fault the universe or God or whatever hated Dean, it was just that…
I know how my story ends. It's at the edge of a blade or the barrel of a gun.
...he couldn't bring himself to believe any more.