What if Dean said I love you in Goodbye Stranger?
“This isn’t you. Cas, I know you’re in there. I know you can hear me. Cas, it’s me. We’re family. We need you; I need you.” Dean is on his knees begging and there’s one more thing to say. It’s on the tip of his tongue.
“I love you.”
Cas’ blade is raised over Dean and his eyes clear, just for a second, a micro second, but it’s enough time. He makes the decision the only one he can make, the only way he can see to putting a stop to this. He plunges the blade down hard. Straight into his own chest.
The room flickers furiously from Naomi’s office to the warehouse as he falls.
“Castiel, what have you done?” Naomi cries, but he thinks maybe Dean does too. There’s Dean’s hand on his shoulder, he can feel the warmth of his palm.
“I do what I have always done, Naomi, I fought.”
“You fought, that didn’t look like fighting to me, it looked like giving up!” And yes, that’s definitely Dean’s voice.
“I did what I thought was right,” he chokes out. Words are getting harder now, sticking together like wet sand.
“And that was killing yourself?” Naomi barks through the air but her face is gone.
“And that was saving Dean Winchester."
Somewhere he thinks he hears Naomi laugh at the same time he hears Dean sob out loud.
And then he hears nothing.