"I can't."
Dean sighed tiredly, rubbing a hand over his forehead. His eyes were squeezed shut in exasperation.
"Goddammit Cas, just try." He wearily muttered. Dean was getting too old for this. Dean and Castiel had been sat in the small box room for about an hour now, and even with Dean promising to sit with him, Cas had refused to sleep. His long skinny legs were crossed awkwardly beneath him, covered in blue plaid pyjama bottoms, which may or may not have been donated to him by Dean, and his hands fidgeted in his lap. He sat bolt upright on the thin metal bed with the grey sheets that had been crammed into the makeshift bedroom that just happened to be next door to Dean's.
"I mean come on, what are you, twelve?" At this, Castiel looked up with those big wide eyes. He blinked.
"Dean." pleaded Cas. Dean had never noticed before, but now that Castiel never wore his shoes, he could see that when Cas became uncomfortable, he had a habit of wriggling his toes. Eyes flicking down, he noticed the tell-tale squirm through his socks.
Perhaps Dean was being too hard on the guy. He himself had never been in this situation before. Ever since Cas fell, Dean should've known this would come sooner or later. He'd done his best helping him adjust to most things. For example, eating, and what happens after you eat. Dean shuddered. Never before did he think he'd be helping a grown man do that before.
But sleep seemed like a no brainer to him. Just something he did, something that everyone did. It confused him that Castiel found it weird or daunting – it's just a part of human life.
"I'm scared." Cas mumbled in a small voice, his eyes avoiding Dean's. There were times when Dean found Castiel absolutely terrifying, like when he was smiting demons on hunts, or finding out there was no pie left in the corner store, but he never thought he'd be seeing this side of his friend.
Maybe it was the sudden humanity burning through Cas' system that wore his shields out, leaving behind the raw person that was now exposed to Dean. He softened slightly under the intense gaze of the angel-turned-human sitting gangly on the bed.
"Look, Cas." Dean said softly, shifting onto the bed beside him. "I know this whole situation is whack, but you gotta sleep sometime."
Cas nodded numbly.
"I mean, you are human right?" Dean joked. Seeing the hurt in Castiel's eyes told Dean that it was too soon. Another tactic then. "It's really not all that bad. It's…it's like drifting."
Knuckles gripping the sheets, Castiel leaned towards Dean's shoulder. Dean tensed up, unfamiliar with the contact, but eventually relaxed as he felt the warmth of his friend beside him.
"I'm tired, Dean." Said Cas drowsily. "I'm just really tired."
Dean reached an unsteady arm around Castiel, cradling his head between his own and his shoulder, his thumb gently rubbing against the skin on his upper arm.
"I know." He whispered. "Just go to sleep. I'll be here."
Cas' body melted into his, and Dean lay them both gently down, squeezing tightly together on the thin bed. Dean could feel each breath Cas took, as his arms encircled the man, and his heart beat soundly against Cas' back. Soon Castiel slipped into unconsciousness, his hands tightly wrapped around Dean's arms, curling back towards him. With each tenuous breath, Dean found himself relaxing, and also joining Castiel in the soft, warm comfort of sleep.