It could be considered bi-bro if you're discerning by actions/who's driving the plot. It was certainly a great showing for Sam in any case.

I went looking for those destiel posts and found a person arguing that "the man I love" couldn't have Dean thinking about Sam because it was too romantic a phrase to relate to a brother. And that the entire Corbin/Michelle subplot was a Dean/Cas mirror. And that the entire episode was framed around Dean's fear of losing Cas, starting with the obligatory "this is why not pursuing the mytharc this week doesn't mean we're callous assholes about our friend's situation" convo between Sam and Dean. So, yeah. Shipping goggles are amazing. But I don't get why they're necessary--Dean caring about Cas and fearing that they might lose him for good has been there in the text, there's no need to read stuff in where it doesn't belong.

I've also seen people saying Billie was wrong and Dean really did want to save Sam out of a sense of general altruism/to defeat Amara. Which, I was touched when Dean said that/had faith in Sam's abilities even though I very much doubt Dean was doing long term strategic calculations in that hospital bed, and clearly Billie was intended to be the cold clarifying eye about his motivations this season.