I just wanted to draw your attention to something I noticed while looking at 7 million gifs of this scene
This is Dean’s reaction to Cas’ “you’re my family… I love you” He’s full of pain, but is looking away because that what Dean does with his emotions.
This is Dean‘s reaction to “I love ALL of you.”
Just like us, Dean, has heard the distinction, and realised what that means, that Cas loves him in a manner unique to his love for the other Winchesters.
This is the face of a character who canonically just heard a confession of love. That is a “did he just?” face.
This is “you’re my family I love you” moose, with serious sad brows
This is a “why did he just say all of - OOOOOOOOhhhhh.” lightbulb moose (ill admit, its more distinctive on film than still image)
Let the record show that on episode 12.12, at 31:24, both Winchesters had canonically realised that Cas loves Dean - not as a snarky joke from an enemy, not a awkward misunderstanding of human personal space, not just friends - but real love.