Dean was shaking. He had been, in a lowkey way, trembling since Cas drove the blade through Billie’s chest. He understood completely why Cas had done what he did, but he couldn’t help but think there were serious repercussions on the way.
He stared blankly ahead, watching street lamps and signs fly by outside the rain splattered windows. Sam was leaning back in the passenger seat and, judging by the way his head kept flopping around every time Mary took a high speed turn, his baby brother was likely sound asleep.
Dean felt some relief at that. If Sam was sleeping, that meant he felt comfortable enough to do so. He felt safe. If Sam felt safe, maybe Dean could stand down. Maybe he could relax a bit himself.
Watching Mary watch the road, he wondered where she’d gotten that intense focus. God knows he’d seen that expression in the mirror a few times. She drove like him; sure, determined, and more than a little too fast.
Beside him, Cas stared out the window into the night. Something was up with Cas. That had been obvious before he so efficiently exterminated Billie.
“Cas?” Dean whispered, so low that he didn’t think Mary heard him.
Cas turned from the window and looked back at Dean, his eyes wide and sorrowful in the dim light coming from the dashboard.
“You ok?” Dean murmured.
“Shouldn’t I be asking you that?” Cas quietly rumbled.
Dean cocked a wry grin at his friend, reaching across the seat to take his fingers in his own. Cas glanced down at their joined hands, and the ghost of smile tilted the corners of his mouth.
“Let’s just be not ok together then,” Dean suggested softly.
Cas nodded and tightened his grip on Dean’s hand. As Dean felt his body finally start to relax, felt the trembling finally subside, he caught his Mother’s eyes in the rear view mirror.
There was no judgement there, just acceptance and a mother’s love.
Dean relaxed fully into the seat and let his head drift over to Cas’s shoulder. He followed his brother into peaceful sleep.