Dean: maybe I should tell Castiel I'm in love with him

Deans brain to Dean: tell him he's your brother and you're just friends

Castiel: maybe I should tell Dean I'm in love with him

Castiel's brain to Castiel: do it in front of his whole family to make it no homo

Sam: maybe I should tell Dean and Castiel I'm okay with it if they want to be together

Sams brain to Sam: just sit back and watch them struggle to try and show their emotions