I think it goes without saying that the Winchesters are not your normal family, but that doesn't mean that they don't experience the normal ups and downs all families experiences. There are disagreements, some nasty fights, some misunderstandings, and at the core of it all, love for each other.
Sam and Dean have had very different relationships with their father, something with which most of us can identify. For those of us with close relationships with our fathers, or even those who don’t but wish they did, Dean’s unquestioning loyalty to John is understandable. But for viewers who may have had strained relationships with their dads and not seen eye to eye, it’s easy to identify with Sam. He feels John never understood him, and Sam resents how the hunting took over every aspect of his life as he grew up. That’s why he’s so resistant to being pulled back into that life in the Pilot, at least until Jessica is killed by the same demon who killed his mother and set his family on the hunting path.
The brothers seem to switch viewpoints after their dad’s death, and the reasons are also easily understandable. Dean grows angry with his dad because he sacrificed his soul so Dean could live, and John weighs Dean down with an even heavier and more horrible responsibility — the knowledge that he might have to kill Sam if he turns evil. Sam, on the other hand, feels guilty that he fought so often with his dad, his only living parent. That during their last conversation, he tried to pick a fight with John. That guilt (which we all agree Sam is really good at taking on himself) leads to the need to hunt more because there is one less hunter to fight the fight. Part of him also wants to honor his father’s memory, to finish what John started. The switch is shown in “Hunted” (2-10).
Dean: “Screw the job.”
Sam: “You can’t run from this.”
While Sam and Dean also often argue over their views of their dad and how to deal with particular hunts, they are undoubtedly devoted to each other. Each would willingly die for the other. Dean is Mr. Keep Everyone at Arm’s Length, but his family is everything to him. After his father’s death, Sam is his only family. He’s been watching after Sammy his entire life, and he’s not going to stop now. We see the depth of that devotion over and over, as in “Born Under a Bad Sign” (2-14) when Sam asks Dean to kill him. Dean says, “I can’t. I’d rather die.” Sam was possessed by a demon at the time, but Dean didn’t know that. Even thinking Sam was starting to give in to evil, he couldn’t kill his little brother.
This not being able to let go of Sam is pushed to the extreme when Sam dies at the hand of Jake in “All Hell Breaks Loose, Parts 1 and 2” (2-21 and 2-22). In ironic contrast to what he condemns Evan for in “Crossroads Blues” (1-8), and the action for which he’s angry at his dad, Dean makes a deal with the Crossroads Demon to bring Sammy back to life in exchange for his own soul. Even when the demon only gives Dean one year to live versus the customary ten, Dean makes the deal. And he makes no apology for it when Bobby figures out what he’s done and confronts him about it.
Dean: “I couldn’t let him die, Bobby. I couldn’t. He’s my brother.”
Bobby: “How’s your brother going to feel when he knows you’re going to hell? How’d you feel when you knew your dad went for you?”
Sam shows that same unwillingness to let go of Dean in “In My Time of Dying” (2-1). When he and Bobby are looking at the demolished Impala, this exchange shows that Sam is not about to give up on Dean.
Sam: “Oh man, Dean is gonna be pissed.”
Bobby: “Look, Sam...This just ain’t worth a tow. I say we empty the trunk and sell the rest for scrap.”
Sam: “No. Dean’d kill me if I did that. When he gets better he’s gonna want to fix this.”
Bobby: “There’s nothing to fix. The frame’s a pretzel, the engine’s ruined. There’s barely any parts worth salvaging.”
Sam: “Listen to me, Bobby. If there’s just one working part, that’s enough. We’re not just gonna give up on...” (voice trails off)
Bobby: “Okay. You got it.”
When he finds out about the deal Dean made with the Crossroads Demon to save him, Sam makes it his mission to find a way to save Dean. Even when Dean is seemingly accepting his fate by living a hedonistic lifestyle of women, beer and loaded cheeseburgers, Sam is searching every nook and cranny of the lore to find a way to get Dean out of his deal. And when he can't save him, what does he do? He tries to make the same deal with a demon to bring back Dean as Dean made for him. Sigh. These Winchester men just don't learn, do they?
The type of dedication Sam and Dean show each other is powerful, the Supernatural world's equivalent to what many of us would do for a loved one -- anything possible to save them from certain harm or death.
So, what's your favorite Supernatural moment that shows this intense family dedication?