Before, when he'd been merely mortal, he'd always imagined Hell as a crowded place, souls and demons and furnaces all stacked on top of each other. Time doesn't really mean anything, but if it did, he could count days--weeks, years, endless millennia--between encounters with anyone, tormented or tormentor or futile escapee. He always burns them away into nothing, of course, regardless. Anyone down here is a danger to Dean, and that's all he really cares about anymore.
Dean's soul is healing still, so Sam keeps him tucked away in a tiny corner that doesn't really exist except for the two of them, like some shadow-shrouded memory only they share. There's not much to it except a deep bed and a deeper fireplace, a single nightstand with a broken light and a bottle of cheap-tasting whiskey that's never quite emptied.
And Dean, of course, which is all that matters. Not that he does a whole lot except sleep, but--his soul is still healing. Sleep is probably for the best.
Sometimes he rouses at Sam's arrival, pushes himself up out of bed--hair sticking out in all directions, drowsy and slow and always pleased to see Sam. They usually don't talk much, just sit shoulder to shoulder on the end of the bed, sharing the whiskey and whatever memories Dean's dreamed of since Sam's last visit. Sometimes he continues to sleep, a near-boneless bundle sprawled across the bed, with the light of the fire flickering across one pale shoulder or picking out the delicate shell of an ear. Sam stays longer when that's the case, leans against the bed and watches and wonders a little at the peacefulness of it all.
For a little while, he can forget the fire that always smoulders beneath his skin, can simply breathe and love and remember what it meant to be happy, long and long ago.
Technically a timestamp for 3. Arsonist's Song, but mostly I just really like this gif (for which I've lost the provenance):
