Dean and Sam had had a few fallings-out and were working on trusting each other again. Part of that trust could only be earned by spending time with each other, doing all the little things they knew and loved. The other part revolved around keeping Castiel on the straight and narrow.
He was Dean's angel, but Cas had saved Sam's ass more times than he cared to remember, and seemed to genuinely care about him. This may have been his loyalty to Dean, as Cas had once so delicately put it, "I care about him, and he cares about you," but Sam liked to believe he had a friend in Cas even if they weren't both so utterly dependent on Dean Winchester.
The truth was, Dean Winchester was co-dependent on both of them, too. No-one knew him or loved him, all his quirks and moods, like his baby brother, the boy he'd practically raised and taught all manner of things. And no-one had gone quite so far to save him as Castiel had when he'd raised him from hell, and kept risking his neck for him afterwards, being banished for his troubles. So when it became obvious that the angel, cut off from heaven, wasn't coping quite so well with an absentee father figure, there was really only one person Dean could ask for help.
OOO
"How's that hangover doing, Cas?" Dean smirked as the trio made their way to the diner down the street from the motel. He received only a groan in response. The angel was starting to realise that there were consequences to him drinking the liquor store, and he was still suffering a week later. Dean was on his left, and Sam was on his right, and they had both linked arms with him, partly to look after him and partly to make sure he didn't do a disappearing act when they were having a rare afternoon of normality.
At the diner they took a corner booth so Cas could remain between them. Anyone looking at them could tell they were extraordinarily close and comfortable with each other, something the waitress picked up on as she took their small and simple order, but she didn't pry further.
When the three hot chocolates arrived, they arrived with a mountain of cream and chocolate sprinkles as well. The trio waited until the waitress had gone back to her place behind the till, then lifted them to their lips almost simultaneously, Sammy making a murmur of delight, Dean shaking his head slightly as he felt the slightly bitter chocolate slide down his throat, and Castiel blinking in surprise as the sprinkles went up his nose.
"Good?" Sammy asked him. It was Castiel's first taste of hot chocolate.
"I think I like it." He smiled.
"You're better off with these than all that liquor," Dean muttered, "and I never thought I'd be saying that." He swirled his finger idly through the cream on his chocolate and brought it to his mouth, tongue darting out to catch it before he sucked his finger thoroughly. Cas and Sam watched him, captivated by the display in front of them. Dean noticed and winked, making Sam half-think he'd done it on purpose.
Cas took a deep gulp of his chocolate, burying his nose in the cream. He didn't seem to notice a glob of it sitting on the end of his nose until he heard a small intake of breath from both Sam and Dean. Cas with cream on the end of his nose looked devastatingly cute.
Sammy reached out gently and touched the end of Cas' nose, wiping off the cream before licking off the finger, earning himself a dazed look from the angel. Sam could see Dean's face behind Castiel; his eyes were full of love, though Dean would never have admitted to it. Under the table, over Cas' lap, Dean reached out and squeezed Sammy's hand gently. Then both their hands fell to Cas' legs, each resting on a thigh.
If the waitress noticed the sparks flying over on table three, she didn't show it. They stayed a while, messing around with the cream and finishing the chocolates, then she saw them getting up and leaving the bills on the table. The man in the cream trench coat between the other two looked a whole lot better than when he'd come in- his skin was looking more healthy and he had a smile on his face instead of a pained expression.
She nodded politely to them as they were leaving, curiosity turning her eyes out of the window to see where they were going. They stopped at the kerb and all three linked arms again before crossing the road. As they got to the other side a truck went past obscuring them from view; but not before she could have sworn she saw the two men on either side lean in tenderly and kiss the third man on the cheeks.
When the truck had passed, they were gone.