It’s 5 o’clock in the morning when Sam hears a knock on his door.
“Yeah, come in.”
Cas slides in and carefully shuts the door behind him. He’s wearing flannel pajama pants and one of Dean’s t-shirts. “Did I wake you? I’m sorry, Sam. I had to do this before your brother wakes up.”
Sam sits up and tries to look attentive. “Yeah, dude, it’s fine. What’s up?”
“I know that American tradition requires that the man ask the father for his daughter’s hand in marriage, but considering our circumstances, I thought this might be the next best thing.”
“Cas, what the hell are you–”
“I would like to ask your brother to marry me.”
“And it would…mean a lot to me to have your permission. Before I ask. I want to ask tonight.” Cas folds his arms over himself as if he’s actually nervous that Sam’s going to say no.
Instead of responding right away, Sam crawls out of bed and walks over to Cas to wrap him in a hug. “Of course you can ask Dean to marry you. That’s–really, that’s fucking thrilling news, man.”
They pull away from each other, and Sam feels himself tearing up at how ecstatic Cas looks.
“Yeah, Cas, really. I mean, you’re family already. This is even better.”
“Thank you, Sam.” Cas’ demeanor changes before he says, “I have to go. I have a lot to plan.”
An hour later, Sam and Dean are sipping coffee in the kitchen while Cas is “out running errands.”
Out of absolutely nowhere and with no preamble, Dean states, “Dude, I think I want to ask Cas to marry me.”
Sam chokes on his coffee.