Specific Fic: (not related) Dean x Sam Mental Hospital au
I read this fic a year or two ago.
(i don't know if these are correct) In it sam and dean are not related. Dean had been at the hospital for a while. Sam is new to the hospital. Sam had been seeing lucifer everywhere. When he was with dean, lucifer was at bay. Dean was in the hospital for trying to kill himself too many times. It started one time in the kitchen with his dad. He had dropped a knife he was using to cut vegetables, when dean tried to catch it he cut his hand. Dean began to cut whenever his dad got mad. Then it became a habit. In the hospital they don't even trust him with a plastic fork. Dean is on cut watch. Everyday they would come in and check him. Dean is in the hospital by his own choice. Every time they would try to get him to leave he would say he'd end it the minute he got out. Sam helps to calm him and Dean makes lucifer go away.
here's a quote i remember: (sam and dean are going to shower together when sam sees the cuts) "don't go all lovey dovey on me. Don't try to kiss my scars and say they're beautiful."