[The worry he sees on Steve's face is something he can relate to. He's worried about Bucky, too, but even with that he knows it's different when it's with your own best friend. With your brother. It just is. He draws in a breath and lets it out slowly, leaning back in his chair.]

Steven, listen. Whether it's because of this door thing on the Mirror barge or PTSD or both...we'll help him. We'll figure out how to help him. Look, I don't know if you've met Jean, but she's really good with this kind of stuff. I've been talking to her about some stuff back home.

[He twists his fingers together in his lap.]

And if anyone is gonna be able to get through to him, to help him, it's gonna be you, man. [There's no doubt in his mind about that.]