They never said, "I love you." Not once.
Not when Dean was dying. Not when Sam lost Jess. Not the night they tried to shoot the devil. Not the day they did. Not once. Some strange, macho, man-pride thing was the excuse, of course, because Dude. No chick flick moments is a hallowed phrase much to be revered for the sake of the Winchester honor. But really, it was because they didn't have to.
Any final words?
I think I'm good.
Winchesters, they say I love you when they call you brother.
It's okay, little brother. Everything's going to be just fine.
They say I love you when they slap you on the back or bump your shoulder just hard enough to knock you over.
So, you got sidelined by a thirteen year old girl, huh? Just saying, getting a little rusty there, kiddo.
Oh, shut up.
When Sam rolls his eyes at Dean, or when he kicks Dean under the table during an interview, that's when he says I love you.
When Dean turns his music up too loud, and like a freaking jerk! asserts his brotherly prerogative ("I'm your big brother, which means I'm always right" No it doesn't! "Yeah, it totally does.") that's when he says I love you, too.
When somebody else calls Sam Sammy, and Sam growls low in his throat like a threat that only Dean gets to call me that and Dean smirks because yeah. They're saying I love you.
When Dean saves Sam's life. When Sam makes fun of Dean's height. When they throw M&Ms across the car at each other because Sam insists that Nina Dobrev is hotter than Reese Witherspoon.
Dude.
When one sits up all night by the other one's bed just to listen to him breathing to be sure he's okay.
When they look at each other like you mean the world to me.
They know.
So why say it? Words cheapen everything they touch anyway. Why risk that? They're saying it all day anyway.