Having a brother who is slowly going insane isn't much of a change for Dean. Once Dean accepts there's nothing he can do, it just means a few adjustments to the routine.
He gets up. Brushes his teeth. Gets dressed. Gets food. Searches the web for news about Dick while Sam scopes the paper for a job. Smiles at the waitress. Pays their bill. Heads back to the motel to change into clothes for the interviews. Sneaks a look at the paper while Sam's in the bathroom. Makes sure the articles say what Sam thinks they say. Fills Bobby's flask. Hears Sam talking through the door. Takes a drink. Knocks on the door to snap him out of it. Asks Sam how he is. On a good day, nods like he believes it. On a bad day, warns Sam not to lie. Clips out the newspaper article. Tacks it to the wall. Hangs the "do not disturb" placard on the door as they head to the parking lot. Starts the car. Pretends not to see Sam press down on his hand as they drive away. Keeps going. Does it all over again the next day.
They practice shooting in the woods with ammo loaded with powered laundry detergent instead of rock salt. Dean fires again and again into the paper target hammered into a tree and is satisfied to see it go where it ought to. Motions Sam to step back farther and tries again. Dean thinks with some pride that he's as good with a gun as his father ever was.
He catches his brother staring at him and can't read the look on his face. "What?" Dean asks. Sometimes the question is all Sam needs to jolt him out of whatever he's thinking. Sometimes he goes for his hand, just to make sure. Sometimes Sam will ask, soft and unsure, "Dean?"
"Nothing," is what Sam says this time. He turns his head back and raises his own gun, shoots the target.
One night, Dean comes back to their motel room from a night at the bar to find Sam mixing gunpowder, the old-fashioned kind, from scratch. Stirring saltpeter, charcoal and sulfur by hand. Sam says it's for the Colt, but they left that back in the Impala's trunk when they put her in storage. Dean's not sure which is worse — the possibility Sam is lying or the possibility Sam forgot — so he lets it go and tries to keep an eye on his brother all through Dr. Sexy.
Sam leans over and takes a deep sniff at the saltpeter, looks over at Dean with significance and shakes his head.
Dean's a fighter more than anything else. But he can't fight Sam's brain. Especially when he doesn't know what it's doing.
Dean knows it's not their car, knows they should just steal another one and move on, but it's been three months since he's gotten to do any car maintenance, and he misses the Impala like crazy. So, when he realizes the oil change sticker on the windshield is months out-of-date he pulls into the nearest gas station, buys a couple of quarts and then finds a nice quiet lane to pull over and work for awhile. Sam doesn't seem to mind, comes and lays down next to the car and keeps Dean company as he works. Dean notices Sam staring at his hands a couple of times, that hot intense stare he's been seeing more of lately that he doesn't know how to read, but it's not like there's anything else for Sam to look at under the car. It doesn't have to mean anything.
Dean stitches up the four long gashes down the side of his brother's arm. Sam seems fascinated by the needle, eyes fixed intently on Dean's hand, as it moves side-to-side taking even careful stitches that won't cause his skin to pucker. "Too close, Sam," Dean breathes. "Too damn close."
"Sorry," Sam says, looking away. "I was … distracted."
"You haven't been sleeping, have you?" Dean asks, though he already knows the answer.
"I'm fine," Sam says.
"You gotta be careful," Dean chastises, as he finishes up. He ties off the thread and lets his fingers linger on Sam's warm skin for just a second longer than he should before he gets up and grabs a couple of beers. "Take this," Dean says, handing one to Sam, hoping if he gets a few in him before bed, it'll help him sleep. Sam can't drink Dean under the table, but he's not sober every night any more than Dean is these days. He leans over Sam and takes a deep breath, gently bonking his forehead against Sam's for a moment. "Too close," he says again.
He starts to lift his head and that's when Sam surges forward, kissing Dean, sweet and wet. Dean kisses back at first, want and need singing in his head. It takes longer than Dean can admit to himself to pull away. But Dean doesn't know for sure who Sam is seeing behind his tight squeezed eyelids, and it's that thought that gives him the strength to pull away, though Dean's been saying yes to his brother all his life.
"Sammy?" Dean begins. "Are you—"
Sam jerks back with a look of shock, turning scarlet and gaping like a fish. "Dean," he says. "I'm sor-, sorry, I—"
"It's okay, Sammy," Dean says, running a hand gently through his brother's hair. He pulls him close and makes sure to keep his touch brotherly. "It's okay." He keeps carding his hand through Sam's hair as his brother starts to drink his beer, and is rewarded by Sam slowly relaxing, his breathing going even and calm. "Everything's going to be fine."
Dean waits until Sam falls asleep. Then he gets up. Showers. Brushes his teeth. Gets ready for bed. Takes the bottle from Sam's hand and puts it on the nightstand. Pulls a blanket over his brother. Lays down. Tries not to want. Sleeps. Dreams.
Does it all again tomorrow.