She can't see the nod that he gives in response to her location, but he gives it anyways.

"Don't worry about it. We'll find him, okay?" It's not a mindless reassurance. It's a promise. It might have taken him three months to find Tony in the desert of Afghanistan, but he'd found him and brought him back home. Whether something happened to him in Germany or not, they'll find him and they'll bring him home, safe.

They always do.