(Jack sighs heavily and runs a hand through his hair.)
JACK: It’s Sam, isn’t it?
DEAN: (He winces but his jaw tightens defensively.) You ever had to watch your little brother murder in cold blood? You can’t imagine what it’s like, man.
(There’s a tense pause. At first, it doesn’t seem like Jack is going to respond, but then he’s speaking, words wrenching themselves from his lips and leaving a bitter taste in the air between them.)
JACK: You’re right, I can’t. But I don’t have to.
(Dean looks up sharply at that, but Jack doesn’t meet his eyes.)
JACK: I watched my brother destroy Cardiff in a day. He killed hundreds – including me and two of my friends. The only reason I was able to stop him was because I got lucky. But you know what? I can’t blame him, Dean. He acted like a monster but I can’t hate him for it, because he’s my brother. And if I’d been there, if I hadn’t let go of his hand, if I’d kept looking for him instead of just giving up… Maybe none of it would’ve happened.
(Jack finally lifts his head to see Dean staring at him, expression decidedly more wretched than before, issues of betrayal and trust and forgiveness warring with each other. The Captain’s gaze softens, and he steps closer until he can reach out and rest his hands on Dean’s shoulders. Dean flinches slightly, because damn, he’ll never get used to how affectionate Jack is with all of them, but he can’t bring himself to protest the other’s touch right now.)
DEAN: The hell am I supposed to do, then?
JACK: Be there for him. No matter what. (He gives Dean’s shoulders a squeeze before brushing past him. It isn’t until he’s halfway out the door that he glances back, the smile on his lips sad but still reassuring.) Also, Dean?
DEAN: Yeah?
JACK: Whatever you do, don’t let go of his hand.