Work Text:
Sleeping doesn't come so naturally to him now that he has fallen--again. Before, a few years ago, the Fall had been slow, pleasant even, compared to now. It has been easy to sleep then because he had been exhausted all the time. There had been battles to fight and an apocalypse to stop, and the time to sleep had been short and precious. His body would succumb to it and he'd give in to the unconsciousness that followed without though.
Sleep is frightful now that time abounds. It's short and uncomfortable and full of visions of falling stars, and Castiel resents the fact that this body needs to sleep, yet can't seem to stand more than a few hours of uninterrupted rest. It makes him antsy and unpleasant to the other occupants of the bunker, he knows this.
Which is why he barely sleeps at night. He wanders the bunker, he scavanges the library for obscure pieces of information and ransacks the artifact rooms, hoping to find something that will entertain him in the wee hours of the morning. Another thing about being human: you get bored.
Some nights, when he feels uneasy and bold and hasn't slept enough in a week, he'll pad the hallways to the last-room-to-the-right and quietly open the door, finding its owner fast sleep, snoring over a warm mattress.
He knows how Dean feels about being watched at night, but it's the only activity that soothes Castiel and fills him with a detached sense of purpouse, which he finds very hard to grasp, these days. So he tiptoes his way into the room, smooth like a shadow, and drops his tired bones on the spare chair at the corner, basking as long as he can in the silence and the warmth of Dean's room, or Dean's presence.
Dean sleeps much better lately, and for longer. His nightmares are scarce and they don't hit as close to home as they used to. He looks well rested, despite the sense of impending doom that always follows the brothers wherever they go. In his bed, he lays relaxed and untroubled, semblance tranquil, shoulders lax. Sometimes he even smiles with eyes closed, and his face lights up despite the lack of light. Castiel waits most nights to be able to watch Dean smile in his sleep again.
Eventually, as the hunter's chest rises and falls and his snores become white noise, Castiel will feel the pull of sleep and allow a deep slumber to take him down, forgetting for a minute about heaven and angels and falling stars. If he's lucky, he'll wake up when the sun is up with a blanket around his frame, and he'll smile.
For now, he's just content to watch.