Disclaimer: If Sam and Dean were mine, I wouldn't be here posting fanfictions about them, believe me! :-D
Note: All the pronouns in italic in the text refer to Dean. Just so that you're not too confused.
Please bear in mind that I'm French, hence the English mistakes! Sorry!
Flames are dancing before his eyes. He usually loves fire. There's something so magical about it. All those shades of red and yellow. The wonderful scent of roasted marshmallows on summer evenings. The comforting heat of the chimney during winter. But this time, it's different. Those flames have just deprived him of his mother. Deprived him of his innocence. Deprived him of his childhood. Far too soon. Sam is six months. He holds him tight in his arms. So tight it looks as though he'll never let him go. It is his job to look after him, now.
Sam is five and he keeps asking more and more questions. But he's still so young. He hates to lie to him, but he just wants to protect him. There's no need for a second child to lose his innocence. Not yet. There will be a time when Sam learns the truth, but for now, he just wants to make Sam's childhood as normal as possible. He lends him his old toys, he teaches him to make paper planes, he watches Thundercats with him and he shares his cotton-candy with him at the funfair. Sam's smiles make him forget everything. About all the dark things he would have rather never learned of.
Some motel in Wisconsin. Sam is about six now, and he has eaten all the Lucky Charms. He didn't even get a chance to eat a few of them. But it doesn't matter, he loves Sam a billion times more than Lucky Charms. Still, that night, he disobeys their father, and leaves Sam alone in the motel room to go and play videogames outside. Sam's nearly been attacked by a shtriga. Of course, that disappointed look on their father's face is like a stab in the heart, but it's nothing compared to the thought Sam could have died because of him. He'll never forgive himself.
Sam is eight. It is Christmas, and he has just discovered their father has lied about their mother, and about his occupation. And he's not even there with them for Christmas. Sam feels betrayed. Angry. Furious. That's why he gives him the present he was supposed to give to their Dad. He doesn't want it at first. But Sam is a stubborn kid, and he has to surrender. He can never say 'no' to Sam, anyway. It is a necklace. With a weird pendant. He has no idea what it is. Some kind of humanoid head with bull-like horns. Objectively, it's rather ugly, but still, it's the greatest gift he's ever been given. Because it comes from Sam. From now on, that necklace is his most precious possession.
Years have passed. Sam is eighteen and he is as wild as a storm. He yearns for freedom. For normality. He's had another row with their dad. A decisive one. He tries to make him change his mind. To convince him normality is overrated. But Sam still is a stubborn kid. His decision is irreversible. He's leaving. For Stanford University. He feels like he's lost half of himself. He feels empty, but there's nothing he can do about this. As much as he hates to admit it, he knows that Sam will definitely be happier that way, and that's all that matters. He wishes he had the guts to do the same, but he must stick to their father, help him find the demon that ruined their family life. And the truth is that he wouldn't want another life. Contrary to Sam, normality scares him. Sure, many times he has tried to imagine what it would be like to get married, have kids. A family. But he can't refrain from hunting. It flows through his veins.
Sam is twenty-two. He hadn't seen him for a long time, too long, and he has to face it. His little brother is a full grown-up now. As expecting, he did well at university. He is a senior at Stanford, and is applying for law school. And God, his girlfriend is pretty hot. Despite the bitterness he still feels, he can't help but being proud of his Sammy. That makes him feel even more guilty to come along and ruin Sam's chance to live a normal existence. Yes, it is selfish. There was a time when he was just dreaming to offer Sam a better life, and now he messes everything up. But their dad is missing, and he is scared, and he just can't go looking for him on his own. He needs Sam. He has missed him so much, and it feels so good to be on the roads again with him. They have to make up for lost time.
Sam is twenty-three now. He is sleeping peacefully. He usually loves to watch him sleep. There's something relaxing about it. Whenever he can't sleep at night, he secretly watches Sam sleep and for some reason, it calms him down. But this time, it's different. Because Sam will never wake up. His eyes will never open up again. The red stain keeps spreading. Sam's blood. Sam is gone. Just like their mum. Just like their dad. He is all alone now, and he just doesn't know what he is supposed to do. His thoughts wander. Memories of their childhood. Memories of their time together on the roads. All those miles they covered. Through the sand of Arizona. Through the snow in Michigan. A tear runs down his face. It tastes of salt and whisky. That damned Whisky which doesn't help at all to ease the pain. It was his job to look after Sam and he's just screwed it up. He has lost everything. He doesn't even feel like it's worth living anymore. So now he knows what he is supposed to do. Because he can't let him go. He buries the box at the nearest crossroads and he makes the deal. It doesn't matter he only got one year. As long as Sam is concerned, nothing matters.
Sam is still twenty-three. He is not asleep anymore, and he doesn't remember well what happened. It has worked, and seeing Sam again is worth all the sacrifices. He holds him tight in his arms. So tight it looks as though he'll never let him go...
The excruciating pain Sam feels in his back will soon be a bad memory. It has to.
"Sorry. I'm sorry, man. I'm just... I'm happy to see you up and around, that's all..."
Thanks for reading! :)