There's more to that story he's not telling, some that he doesn't know the extent of, but he just crosses his arms and nods. Whatever is weighing on his mind is distracting enough to keep him silent for a few beats. Eventually he looks his sister in the eye and smiles again. Never mind if it's slightly forced; he's trying his best.

"It's good to see you." There. He asked her how she was, filled her in on what she needed to know, and told her how their sister is doing. He's checking all of the boxes. "I have no idea how you found us, but it was considerate that you didn't make us go out of our way."