[Hiro laughs, at first, because it takes him a second to realize what Tadashi's saying.]

Hey, he learns pretty well on his - wait. [There's a long pause, and Hiro's gaze slides over to his brother's face, searching and a little concerned.] You know about that?

[Hiro remembers the "heart attack" incident pretty clearly, but Tadashi - well. Wasn't there. But he knows about it.

...And if he knows about that, what else does he know about?

More awkward laughter. He rubs the back of his neck.]

What'd you do, spend all day swapping stories with Baymax?