Every other week or so, Bobby would start awake with a gasp, sitting bolt upright in bed. He would shake his head, as if trying to remove the cobwebs of the nightmare about how his Karen had died. He would wipe his brow of the accumulated sweat. He'd swallow the lump in his throat, and swing his legs over the edge of the bed. Walking softly down the hall, he'd check to make sure both of his boys were sleeping soundly, and then go into the library. He would take a quick shot of whiskey, and then paw through old books until dawn, unable to sleep.
Once or twice a week, Dean would wake himself up with a muffled cry into his pillow. He'd blink his eyes, and brush at the unshed tears impatiently. His hands would be trembling as they remembered how his knife had felt as it carved into souls. Dean would wrap himself up in a blanket, trying to warm up as the light sheen of sweat that covered his body evaporated along with his internal heat. He'd stand unsteadily and will his hands to stop shaking. Stepping out into the hall, he'd glance towards Sam's room to make sure his brother was okay. Then, he'd make his way to the library to wait out the sun. Sometimes, he'd find Bobby there, and the older man would silently pour him a shot. They'd spend the night there, the only sound the occasional turning of a page.
Almost every night, Sam would wake up screaming. As soon as he realized he was awake, his screams would turn into broken sobs. Dean would already have come running by that point. Often times, Bobby would stand guard at the door. Sam would shake violently, sometimes vomiting in the trash can besides his bed. It had gotten to the point that he kept extra sweats nearby, as his were generally drenched in sweat when he awoke. Dean would help him change his clothes, and Sam would work stop crying and control his breathing. The younger man would try to ignore the memories of Lucifer surrounding and permeating him for over one hundred years. Bobby would bring Sam a shot, and he and Dean would each take one too. Dean would sit with his back against the headboard and his hand resting on his baby brother's back. Bobby would bring his chair and book in from the library and post himself in front of the door. Sam would do his best to fall asleep, knowing they were both there to stop Hell from ever swallowing him again. He generally was still awake at daybreak.
Bobby Singer generally sleeps through the night. Though his memories of Karen will haunt him forever, he is an old man, and he has come to terms with the mistakes he cannot reconcile in this life. Dean Winchester often sleeps through the night. He regrets his past in Hell, and wishes to forget the torture that he both experienced and inflicted there, but he has had many years topside to remind him of the occasional good things in life. Sam Winchester rarely sleeps through the night. Lucifer and the Cage are his constant companions and Sam is nearly broken. But he has Dean and Bobby, and so he tries to be brave. So, once in a while, Bobby, Dean and Sam sleep through the night.