Disclaimer: I don't own SPN.
Welcome to the third installment of the Henry Winchester Chronicles! You don't HAVE to read 'Nightmare' (part 2) but if you haven't read 'As Time Goes By' (part 1) then you really need to if you're going to understand exactly what's going on.
"It's all your fault, Sammy!"
Dean tried desperately to stop moving his mouth, to do whatever it took to get rid of that look of utter terror and despair on his little brother's face. But no matter how hard he tried, Abaddon was too powerful and he couldn't overpower her.
"I'm tired of it! I'm tired of you screwing everything up for me! I'd be better off if you were dead!"
He straddled Sam and began to strangle him. As Sam choked and wheezed and spluttered, Dean struggled as hard as he could to pull away and stop hurting his baby brother but no matter how hard he tried, he just couldn't!
'SAM!' he cried mentally. Abaddon's laughter just rang in his ears and Sam's empty eyes stared up at him, the previously bright hazel glazing over – he'd killed his little brother and Abaddon wouldn't shut up and oh God, Sam was dead, how could he betray his brother like that –
"GAH!"
Dean bolted up in bed, breathing heavily and sweating madly. Upon realising that he was alone in his head and that demon bitch wasn't anywhere near him, he let out a small, choked sob and fumbled for the anti-possession charm around his neck. She couldn't get back in! Sam was alive!
"Sammy," he whispered, closing his eyes. When would the nightmares stop? When would he stop dreaming about killing his little brother every night?
Dean suddenly felt an overwhelming urge to go and check on Sam, to see for himself that he was alive. As quietly as possible, he got out of bed, slipped out of his room and crept down the bunker hall to Sam's room, only several doors away. When he carefully opened the door and saw that Sam was shifting and stirring but safely sleeping, he breathed a small sigh of relief. Just as he was about to close the door –
"No," Sam whimpered, shaking his head. "No…Dean…please…d'n't k'll me…'m s'rry…"
Something seemed to punch Dean in the gut. His 'protect Sammy' instincts immediately kicked in and, knowing that he had to do whatever it took to take care of his little brother, he crossed over to Sam's bed but paused. How could he touch Sam after what he'd done? Would Sam even let him? That other night had been a one-off, hadn't it?
But when Sam whimpered, Dean's mind was made up; he crawled in under the covers and held a shaking Sam close to him. Sam stopped shaking straight away.
"It's okay, Sammy," he murmured, trying not to hold Sam too hard in case he scared his brother or an Abaddon memory came crashing back. "She's gone. I won't ever hurt you again."
"D'n?" Sam said sleepily. His eyes were open, staring up blearily at Dean.
"I'm sorry," Dean said, stroking Sam's hair. "I messed up. I hurt you bad. I won't ever hurt you again."
"Not your fault," Sam said with a small yawn. He snuggled further into Dean's embrace, while Dean just kept running his fingers through Sam's hair.
"Go back to sleep, Sammy. I'll protect you. Nothing'll ever hurt you again while I'm around."
Sam sniffled and wrapped his arms around Dean, nearly choking the life out of the older boy. That seemed to be approval enough for Dean to hold his baby brother as hard as he wanted, short of causing him pain, and so Dean pulled Sam closer and tucked Sam's head under his chin.
"Love you, Dean," Sam mumbled. "Don't leave. Stay. Don't leave me."
Something fierce seemed to rise up inside Dean. He'd never hurt Sam ever again! Never!
"No way, Sammy. I'm not leaving for nothing. Go to sleep. I'll take care of you."
It didn't take long for Sam to drift back off to sleep. Dean didn't get any sleep for the rest of the night but Sam didn't have another nightmare while he was there, so it didn't matter. So long as Sammy was good, everything would be just fine and nothing else mattered.