Dean isn’t a dick - he’s a textbook case of grief. The anger, the withdrawal, the lashing out. This isn’t out of character, it’s a reflection of a human being in pain. It isn’t pretty but it’s real.
And their argument at the end? Remember that Sam is the only safe “spot” for Dean to show his emotions - even Jody only gets the “things are dandy” response. Being the recipient of that anger and pain isn’t easy but it’s real.
I’m glad for Sam saying what he did. It’s about time he lost his cool and showed some anger. When Dean loses himself in emotion or denial, Sam counter balances it too far at times by being Supportive and trying to solve the Problem (whether it’s to remove the Mark or train the Nephilim).
The angrier Dean gets, the more supportive and/or accommodative Sam becomes, like an emotional seesaw. Sam pushing back and getting angry means the dynamic is changing.
This kind of conflict is why I watch. If Sam and Dean were always perfect and in sync with each other, the show would be pretty boring.
Why don’t we talk about this more? Dean’s best memories in heaven are ones where he’s trying to make other people happy. Taking Sam out to shoot off fireworks to give his little brother a fun Fourth of July, and trying to comfort his mother when he’s only four years old. Dean is happiest when the people he loves are happy too. Of course, that often works to his detriment (and the having to comfort his mother thing is several shades of fucked up, not to mention he was charged once again with caring for his brother and they were doing something seriously dangerous), but right now let’s just focus on Dean’s kind heart. And how much this man deserves someone who is just as interested in his happiness.
I can’t wait until he accepts for himself that he can have nice things, thus going after them, telling people and letting them do these nice things for him.
Hey Sammy, let’s marathon Disney movies in our pjs this weekend?
Hey Cas, just get in bed and snuggle ok?
These would be moments in his heaven im sure of it and that’s where the narrative is leading - that he will allow himself to go for them now :)