As long as he could remember, Dean Winchester always loved his brother. He barely remembered life without him, really. There were faint memories of a time where it had only been Mom and Dad and him, but he had been only three or even younger and the memories were blurry and broken up, like pieces of an incomplete picture. Dad letting him sit behind the wheel of his beloved car. Mom holding him by the hand when going for a walk outside.
Snippets, really, insignificant but nice.
After that, there always was Sam. Dean didn't remember the excitement he felt when his parents told him about a baby on the way – the pride of becoming a big brother soon, the fascination with which he had watched his mother's belly grow. He didn't remember how he, when the baby was finally there, stood in astonishment, too stunned to say a word, looking at the tiny creature in his mother's arms, either sleeping or crying and barely laughing ever, so fragile and small that it seemed as though a simple touch could break him already. He didn't remember how he promised himself that whatever would happen, he would protect this person, his younger brother, because he seemed in need of any protection he could get.
Dean did remember the day he carried Sam out of the flames of their burning home. The day his life collapsed around him, literally. He remembered his father's tears, much more frightening than everything he had ever seen before, remembered his brother's weight in his arms, remembered his own fear and the heat of the fire – the only reason he didn't drop Sam on the way down the stairs.
The memories had become more and more unclear throughout the years, the pictures vanished, there were mainly feelings now, patches of emotions, blurred together. Ever since that day, he had felt responsible for Sam, the little, good-hearted Sam, who was so easily made the victim. Who seemed to be a magnet for their father's anger because – although he loved the man and admired him dearly – he didn't seem to be willing to obey his orders, the older he got the more he tried to be a person of his own. He was sensitive, not weak, but he preferred books over guns and yearned for friends where his brother and his Dad tried to keep to themselves for their own good.
The more the two of them grew up, the harder it was for Dean to accept that his brother was in fact not dependant on him, that he was able to make his own decisions, to build his own life. They had periods where they hardly spoke, got into arguments almost daily, didn't or didn't want to understand each other.
Yet it was never so much as a question that Dean loved Sam. Sam gave him many reasons to be loved, too. He could be funny. And as much as he wanted to be "normal", as much as he was academically clever, he was a good hunter as well. He was compassionate and probably a little too sympathetic. Probably more than anything he was independent and although Dean loathed Sam's phases of separation, eventually he understood that his determination to make his own decisions might be the quality he admired most about his brother.
There were many reasons why Dean loved Sam, but for Dean, it were the little things that made the difference. It had begun when they were children; the way Sam was eager to learn everything – and literally everything – his brother was doing. How he copied him to a point where it was almost annoying, followed his every step, imitated his way to talk, to walk, to play football. The way he stood in the doorframe after an argument, looking so very small, trying to apologize. It was then that Dean discovered the significant puppy-dog-eyes, an ace up Sam's sleeve that would be dangerous as soon as he learned to use it.
It was the way that Sam would hug him; it happened rarely but with passion, mainly when they were young. The way Sam's eyes lit up with joy when Dean made a joke, or the way he listened attentively when he told him stories, or the way he'd walk up to him and ask him what was wrong when their father hadn't been home a few days again and Dean had started to worry.
When they got older, it was the way Sam looked at him, still, after all the years, with a hint of admiration. His annoying habit to have knowledge of basically everything because he read so much, and share this knowledge unasked, sometimes out of context, just dropping facts Dean didn't think were necessary to know. The way he had beamed, glowed from the inside, after passing his driving test or graduating school. His habit of absent-mindedly scribbling down onto pieces of paper as soon as you handed him a pen and a notebook.
The way he talked about the future, or the past, or even the present, somehow making Dean feel homesick for something he never experienced.
It was the ever-so-slightly-crooked smile, the real smile, the mischievous smile that only showed when they were mocking each other, suddenly making everything seem not quite that bad. Telling him to take care, be careful, don't get dead, light-hearted most of the times but with a serious heaviness in his eyes that made Dean flinch.
And once, once it had been the way Sam had told him "I believe in us." Because maybe that was the only thing that kept the Winchesters going. Faith.
Sam Winchester didn't remember a life without a brother, because he never had a life without a brother. Not having a Mom began to be unusual and bad when he learned that all the other kids seemed to have mothers but having a brother – Sam had always considered it his biggest gift.
For a very long time Sam had been convinced that nobody – and really, nobody! – could be cooler and stronger than his brother Dean. He hunted monsters after all! He was a superhero! He said so himself, and he wouldn't lie, not to him, because Dean didn't lie to him. The first love Sam experienced towards his brother was a very deep, very sincere admiration. Because he seemed to be able to do anything, anything at all. Whatever it was Sam needed or wanted or was curious about – Dean knew. He could make up stories from scratch. He knew how to play football. He was able to provide food whenever their father wasn't around. And he could make the monsters under his bed go away. Only Dean could do that, because only Dean believed him that they were there.
Sam loved his brother because he knew that he would protect him, if necessary with his life. But more than that, it were the little things that reminded Sam how blessed he was.
It was the way Dean explained things so patiently. How it was a matter of fact for him to go and talk to those who had been mean to Sam, give them a piece of his mind. The way Dean always seemed to know what to say or to do, the way he taught him to tie his shoelaces or read him his very first book.
When he got older and the magic started to vanish, he began to see the truth, the grey of their life and suddenly Dean was no longer a superhero but a soldier in their own, personal war, it was his calmness. The way he somehow seemed to be able to fulfil every task he was given. The way he handled a gun with such elegance and routine that it almost looked playful.
The way he'd stand up for Sam, always mediating between their father and him, preventing minor or mayor family catastrophes.
It was that one time Dean had taken him to an empty field, teaching him the basics of driving a car, or the very first beer he'd had with him. The annoying habit of covering him with his own coat when Sam fell asleep in the car or fell sick, although he told him that he was not a child and could take care of himself. The way he'd look him dead in the eye and call him "bitch" for the very first time after a disagreement, catching Sam by surprise so badly that he burst into fits of laughter and the anger was forgotten.
It was the way Dean would step in front of Sam, almost automatically, like it was a reflex, whenever they faced unknown dangers, shielding him from what might come. Sam had begun to mirror this action, unconsciously, because although he didn't actively try to be like his brother anymore, there were certain habits that just remained the same and copying Dean would always be one of them.
There were hundreds, thousands of reasons for siblings to love each other. Billions of ways to show their affection, to prove that they cared. For Sam and Dean Winchester, it would always be the little things.