We pick up this week with Dean looking very alone as he carjacks an old beater replacement (as if!) for his beloved Impala. He clearly misses Sam. Dean’s worst fear is losing the people he loves, so it comes as no surprise that when he bumps into Sam while investigating a suspicious murder, he hustles right over and insists they can at least work the case together.
Sam is one to hang onto his anger and hang on he does, refusing to engage with Dean on any level other than business. As Dean admits, Sam’s anger is understandable. Amy was an important piece of his past and Dean did lie to him. But there is also an element of “little brother Sam” in Sam’s reaction. When he was a boy, he ran away from home, enjoying the respite from his complicated emotions about his family. It never occurred to him what he was putting Dean through, both in losing his brother and in shouldering the blame when their father found out.
Dean’s relationship with his father was permanently affected by Sam’s decision to run away. While a child would never be expected to see the impact on others, an adult is. And I think adult Sam does realize running away is the action that hurts Dean the most. He’s not really walking away from Dean, he’s punishing him. He knows Dean will never stop trying to find him, so he’s not really risking losing his brother.
Sam is still too angry to admit he doesn’t really want to work alone and Dean is not yet ready to spell out his emotions, but fortunately for both, they have a friendly spirit tch tching to herself and deciding it’s time to whack the both of them upside the head. Ellen refrains from actually smacking the boys, but she does deliver a message through a medium to Dean: Start talking to your brother, because you are not all right. She tells him to admit how bad it is and that he has to start trusting again, beginning with Sam.
Again, the build up to the Amy reveal made it believable that Dean takes this advice. We know how miserable he’s been. Dean runs after Sam and admits his lie was hurtful. But he also says he did what had to be done when Sam couldn’t—and that’s what family does. Sam looks like there’s a lot more to be said, but he does listen.