Disclaimer: Sad to say I don't own SPN.
Sorry! Bout Our Luck
Castiel is the brother you never wanted.
The trench coat–wearing, happy–go–lucky, pull–my–finger–and–see–what–happens Fallen angel. An angel you almost wish you'd never met. Because every life you and your brother touch falls to pieces, breaks and shatters until there's nothing but a shadow of what used to be. And it's your fault this time too, and you know it. Maybe you didn't play God, maybe you didn't know what the outcome would be at the time, but you sure as hell didn't stop it.
It might all be funny if the world wasn't caving in . . . again.
The worry for Sam should have melted away, only it hasn't. Just moved on to Cas and the crazy ride he's permanently strapped to. The Lucifer train returned to Hell, you think, but you can still see the searing flames of the Pit in the angel's eyes, know it's nowhere close to being over. A flash of white light, a ruffle of invisible wings, loading of a gun—and you're back in 2014. Where Castiel, one of the Fallen, wears no trench coat, holds no power. Dies because of your future self's actions.
And you call for him, usher him into the motel room while Sam's out getting lunch. Sit him down at the table and play Sorry! to let him know in the way little kids understand. Because now Cas is a kid, rash and unthinking, teleporting all over the world without so much as a second of notice, drunk on happiness—the way you wish you could afford to be.
You promise yourself it won't happen. That he'll stay and choose you, the human he Fell and crashed into Earth for.
It might all be funny if you had all the time in the world that's destined for fire and destruction.
So yeah, Castiel is the brother you never wanted.
But he's family; you couldn't trade him, even if you wanted to.
And, besides, with all those Leviathans on your ass, you can use every man and angel you can get.
Because you've got some serious work to do.