Dean and Sam are aware that Castiel hasn't been being himself lately. He's been down, sad, and hasn't really told them why. They decide to do something nice for him, even if Cas hasn't said anything to them. So one day, Sam takes Cas out all day on a (fake) job while Dean stays behind.
He goes out and buys all new stuff for Cas' room.
He gets him a tv, a laptop, some pictures of flowers and bees, and even fresh flowers for his desk. (he had no idea which kind Cas likes so he got a variety of flowers from the local florist, who also talked him into a vase with painted bees all over it.) Dean gets back to the bunker and he begins decorating Cas' room, making it warm, inviting, and all his. He even installs some hooks on the door for him to hang his trench coat, you know, for the times he chooses not to wear it. The last touch is a new pair of slippers he sets at the foot of the bed, along with a Men of Letters robe which is drapes over the edge.
Sam and Cas come home and Cas heads to his room, maybe to sulk, or stare at the walls, and when he opens the door, his eyes widen. He looks around at all the new things, and his heart is racing so fast, he has to place his hand over his chest. The flowers smell wonderful, and he leans over to bury his nose in them. He's smiling so widely now, staring at the bee vase, and the pictures hanging on the wall. A single tear falls from his eye when he turns to see Dean standing at the doorway.
"You did this for me?"
Dean nods, smiling, and walks over to his angel, concealing something behind his back. "There one last thing, and you're gonna have to zap away my allergies for this, but, here." Dean holds out a little brownish red kitten and Castiel's jaw drops. After Dean sneezes like five times in a row, Castiel places his hand on the hunter's face, gently rubbing his thumb across his stubble.
"There, no more allergies"
They share a smile before Castiel moves to the bed and sets the kitty down on top, watching him roll around, and pounce at nothing, making Cas laugh. Dean joins him, and sits on the bed crossed legged while Castiel lays on his side.
"You made such a big deal when we passed the shelter the other day, so I went back and got him. He's cute, ain't he?"
Castiel nods, holding back tears.
"Whatcha gonna name him?"
Castiel stares closely at the kitty, examining his little face, whiskers, and he notices the cute little brown spots on his cheeks. "Freckles."
Dean laughs, blushing. "Alright then, Freckles it is." Dean takes Cas' tie in his hand and begins to wave it over the kitty, letting Freckles play with it, causing both of the men to laugh.
Castiel's face is beaming, he's brighter than Dean's ever seen him and when their eyes meet, Dean's stomach flips. This is a really good look on him.
"Thank you, Dean."
Dean grins back at his angel. "You're home, Cas. This is where you belong. I just wanted you to know that."
They sit there for a while, staring at each other, as they do best, while Freckles goes into spaz mode with Cas' tie. They're both giddy, light, and this is exactly what he was aiming for. Stealing glances at Cas while he relishes in the pure enjoyment Freckles is giving him, Dean files this moment away in his brain and knows he can reach for it whenever crap gets too heavy for them.
Sam enters the room, pausing to take in the scene. He reaches for his phone in his back pocket and begins to take pictures, smiling wide at how happy the two of them are.
Sam smiles at his brother and friend. "Welcome home, Cas."