Gabriel rubs him the wrong way; has since they’d met. Even though he doesn’t remember it, Gabriel did technically kill him over a hundred times, and he’d trapped them in tv land for days. But no, Dean’s not complaining. He really isn’t.
“But you are,” Mary threw back at her son over her coffee cup. The dinging of a bell behind them signaled a server over to pick up the food. He rolled his eyes at her but she kept talking. “You don’t see it, okay, then maybe you should look.”
He scoffed at her quietly. “What’s that supposed to mean?”
“I mean,” she emphasized. “Look at them, how they interact, how they move around each other. It’s like a dance, and hey, I’m not saying Gabriel’s winning any awards for best boyfriend,” Dean grimaced at the fact his mother was calling Gabriel Sam’s boyfriend. “But he really cares about Sam. He makes a hell of an effort. Watch them. You’ll see what Sam sees.”
And Dean drops the conversation. He’s not gonna watch them like some weirdo, absolutely not.
Except he does it without realizing.
He’d catch himself standing just on the edge of the war room, hunters zipping around, Gabriel bringing Sam a cup of herbal tea and making him sit down for five minutes to do nothing but drink it and close his eyes. He’d watch as Sam would lean his forehead into Gabriel’s after a particularly hard hunt, Gabe wrapping his arms around the hunter and rocking side to side in their hug to calm and ground him. He’d catch them sharing a quick kiss outside the diner, separating with twin grins on their faces a mile long. And Dean thought, huh, yeah, yeah, yeah, okay mom. Sure. You might be onto something.
But it wasn’t until a month later that it really made sense to Dean.
It was late, or, really early, rather, and Dean couldn’t sleep. He felt wide awake, wired in ways he hasn’t since he’d gotten outta hell over a decade ago, and he’s desperate for some milk to fall asleep, not that'd he'd actually admit that to anyone out loud. As he’d made his way to the kitchen, he heard sound coming from the Dean Cave™️, and decided to stop to see what was up. There, sitting and watching a documentary on blue holes is Gabriel, a big mug of something in his hands and ridiculous looking kitten slippers on his feet. He rolled his eyes and kept walking, but as he left the kitchen, he saw Sam shuffle into the Cave™️ on tired feet.
“Hey,” he heard Gabriel softly say. “Can’t sleep?”
Dean knows well enough to not go and spy on his brother and his brother’s - barf - boyfriend. It’s not that Dean’s homophobic, it’s just that Sam could have chosen literally any other guy and Dean wouldn’t have had an issue. But Gabe? He knows better, but he still sneaked close enough to peek at them.
“No,” Sam said dejectedly, sitting on the couch close enough to be on Gabriel’s lap.
Gabe moved a hand to Sam’s head, combing his hair back repeatedly. Sam leaned his head down, wrapping his arms around Gabriel’s waist and hiding in the angel’s chest. It was a safe feeling, to be wrapped up in someone like that. GOD knows Dean loves being wrapped up like that too, but he'd never actually ask. But Sam's different. “Hey,” Gabriel said even softer. “Hey, come on. Talk to me.”
Sam took a gasping breath in. “It’s just… just-“
“Nightmares?” Sam nodded quickly. The documentary washed them in dark blue, Gabriel wrapping them up in a blanket he snapped up, big and grey and fuzzy looking. “It’s okay, I got you. You’re safe, okay? You’re safe here, Sam, safe with me. I gotcha, and I’m gonna wrap you up,” he continued, voice a little playful now, but still soft and full of concern. “Wrap you up like a little burrito. Gonna be my bae-ritto.”
Sam snorted in response and it’s clearly a happy snort if Gabriel’s resounding smile had anything to say about it. “You’re ridiculous.”
Sam shook his head, but turned to face the tv, still wrapped in Gabriel’s arms and the blanket. Dean can see Gabriel snapping up a footstool, letting Sam stretch out while resting his head on the trickster’s chest.
“Was it hell?” Gabe asked. Sam nodded. “Wanna talk about it?”
“No,” he croaked in response.
Gabriel leaned down to kiss the top of Sam’s head, nodding as he did. “I get it. It’s okay. You don’t have to tell me now, but I’m here for you, you know that. I got you, always.”
And then Dean gets it, he really, truly does. He walks back to his room in a daze, missing Sam’s response because his mind is blown. Gabriel gets it because he gets it. Gabriel’s been to hell and tortured for 7 lifetimes. Sam’s been tortured in hell too. They both left home because their fathers didn’t think they should go their own way, they both had older brothers with issues, they understood each other’s fears, their pain. He saw it now, and he felt stupid as hell for not seeing it before.