Graves is patient, waiting for him to collect himself. He doesn't need Credence to force himself into a position he's uncomfortable with, and when he finally settles in -- albeit looking a little more defeated than before (Graves doesn't see why; he'd just survived being struck by lightning, which can be considered a near-miracle).

"I'm fine." Some very minor burns; it's nothing he can't take care of himself. And as for the tiredness, it doesn't matter. Graves will get over it soon enough, and Credence's gratitude is acknowledged with a faint nod. He had been concerned, worried -- beyond his abilities as an Obscurial, he is also someone MACUSA had failed, someone they were supposed to look out for. And while Graves doesn't personally take on the blame (it's a slippery slope, and you just can't save everyone), he takes responsibility for him here.

"Your heart stopped, for a little while. I managed to bring you back. Does it still hurt?"