If Tony had noticed a pregnant pause was happening, it hadn't been nearly enough time to prepare him for the change of candor. More than happy in the safety of the superficial, he stuttered awkwardly again, mouth open and clutching for dear life a pair of canned peas he had been checking for dents. At least Kate wasn't crying, but maybe this was a little bit worse; this didn't allow him 'visibly upset' to react to and do his pantomime of awful comfort. This was just...loss? Acceptance? Frustration?
"Were you close?" Tony didn't know why he said that. Okay, a little bit; without any siblings of his own, the best way to frame the situation for himself to try to understand what Kate was trying to tell him was considering how he would react if his mom got bit. If she was still here and he had to leave her behind. And everything he thought he felt about that seemed very mechanical; do what was necessary, maintain order, consider the outcome above the process. That probably wasn't anywhere close to right. He should have used the present tense. He emptied his hands to reach, first a little inquisitively, is this okay?, then welcoming, trust me, if you can, to take Kate's hands away from her chest. If nothing else, that was an armor Tony recognized.