They warn him, very graciously, that the visit may be alarming. The work they're doing with Khan is abnormally intense, and the effects of it can be shocking.

It's true. The room they're keeping him in is lush, utterly humane, but the man pressed under the blankets is a far cry from the force of nature that helped Kirk take out the Vengeance with almost physical strength alone.

"They said you were coming." He observes, managing to sit up a little. "They eased up on the... pressure, I suppose, so that we could talk."

For that reason alone he looks glad to see him.