The Bunker’s quiet but for the sound of Dean’s and Sam’s footsteps that Cas follows. He keeps his distance, lingers behind when Dean reaches for the chair.
“We’ll get her back,” Cas assures faintly, though he should be the last one to speak. It’s all his fault, achingly, fully. It’s him who deserves to be stuck in Lucifer’s nightmare world, not Mary.
He gets no reply, not from Dean, not from Sam. What could they say? We can’t. We will. The world be damned.
Dean pours three — four fingers of whiskey into his glass. With a glance, offers one to Sam, but Sam refuses. He doesn’t comment on Dean’s choice of coping tactic, either. There’s no offer for Cas, Dean puts the bottle down and takes a sip; he knows — Cas is guilty.
Cas did nothing while his mother fought Lucifer and dragged him back into his hell of a world.
Cas let the portal close behind her, let Dean drop to his knees, broken. He’s never seen Dean so broken.
It all happened so damn fast.
Sam clears his throat. “We’ll figure it out,” he promises, moving a chair out for himself.
Dean snorts, an ugly, mocking sound. “Which part?”
Sam opens his mouth to reply, hesitates. A slow draw of breath, head hung low, not daring to look at Dean. “Mom.”
“Oh.” Dean nods. “That I know.” He takes a long sip and sets the glass down with a loud clank. “We’re getting mom out, I don’t care what it takes.”
For a moment, tension in Sam’s shoulders forebodes defiance, a rightful one. One Cas has no strength for. All he can muster is a sad smile. It’s a huge mistake, a horrible and dumb one. And made out of love — the kind of mistakes the Winchesters never once shied from.
Cas couldn’t stop them if he tried. Even if every part of him rages against the very thought of letting Lucifer out, of giving him that chance once again. Like they did last night. For one bright, painful, terrifying moment he was back in this world.
And then he wasn’t.
And Dean was left kneeling in the dirt, unresponsive.