Why is it even a debate that Dean doesn’t reciprocate cas’ feelings!!They were literally in a life or death situation!! I didn’t take his ‘cas don’t’ as a rejection, and you can see that neither did cas. It was more of a ‘not now, not like this, not after everything’!!! They have spent so long loving eachother and dancing around eachother. they haddd to be aware of the depth of eachother’s feelings (even if they didn’t think the other also felt them romantically), if not because of the very obvious way they treat eachother differently than anyone else, then at least because of the dozens of times someone else pointed it out. Also dean literally ran to the door when he thought cas was calling him post confession!! And he told chuck to bring him back, mentioning only cas by name, and mind u he is exchanging not only his own life but sams life as well. And of course that deal is to bring everyone back, but cass didn’t die as a result of chuck’s punishment, bringing cas back is asking for a favour!!
Years later, and I think we should talk more about Dean blaming himself for Cas' death. Cas calls him selfless, loving, and the most caring man on Earth. In every word, he says Dean is a man worth loving and worth dying for. But before Cas' declaration, Dean says that he led them into a trap because he was angry and needed something to kill. He is already taking the blame because he was the one who said they could kill Billie, and Cas tagged along. I'm pretty sure Dean knew Cas would because, of course, he would.
The point is, imagine everything that went through Dean's mind after Cas' goodbye, knowing how Dean is: "If Cas hadn't come with me, he would be alive."If I hadn't led us here, Cas would be alive."If Billie had entered sooner, Cas might be alive, or at least I would have died with him."If Cas had stopped when I asked him not to do this, not now, he'd be alive."If I had agreed to fight Billie, side by side, he would be alive."If Cas had told me about the deal, Cas would be alive."If he hadn't loved me, he would be alive." "If just loving me hadn't made him so happy, he'd be alive."