Kurama doesn't point out that Hiei was being cautious now, trying to avoid being ill. He does, however, point out the other ways in which it has been true in the past, as if the answer were obvious, all things considered. He expected Hiei not to push himself to the point of illness in front of his sister, which the fire apparition knew would only make the hovering and worry worse, and yet...

“When Yukina is involved, usually.”

He expects that Hiei's patience for all of this is running especially thin. Going from total rest to a glimpse of recovery only to backtrack so severely is probably not doing much for his pride, either. At least, as far as the fox is concerned. While he's been no stranger to napping for several straight hours when needed, this was stretching on far longer and not exactly caused by a life or death situation.

Supervision is one thing, but Kurama certainly doesn't expect Hiei to be up to any actual training himself come morning. Especially now. Not that he's going to mention it, at the moment, instead focused on the tea.

“Of course, it will only be a moment.” Kurama tries not to be too obviously relieved by the fire apparition accepting the offer, tone as neutral as possible before he turns to head for the kitchen. Already mentally putting together the best combination for Hiei's needs as he steps back into the building to get to work.

“Hiei... I realize it is not in your nature to do so, but try to take your time.”