It wasn't surprising to Dean when Sam uttered that he was depressed.
And no, not depressed like sad. Not depressed like he had a bad day and couldn't get over it.
Sam was depressed. Loneliness and the thought of oblivion creeping into bones and blood and controlling the blade that dug into skin.
He wasn't surprised, though.
He knew Sam and Sam knew him. They could read each other better than an author could read their own book.
Because they were each others.
Dean was Sam's everything. His big brother, his father and mother and sibling and best friend all rolled into one package.
Sam was Dean's everything. Son, little brother, and best friend in one sentence, one word, one feeling.
So Dean wasn't surprised. Neither was he sad about it or depsiared, because he knew he could fix it.
Because Dean, the big brother, fixed everything.
And eventually the cuts disappeared. Sam could breathe easier and deeper. His little brother could smile without it being fake, even if it was only for a second.
Because Dean fought monsters that even he could not see.
And won.
Just like Sam did.