[Hiccup understands, which is why he lets her complaining go without judgement. He had been lucky enough to be greeted by Toothless when he arrived in Johto, though the Night Fury had long-since left. While he went through his day-to-day life feeling more than content, not having his favorite, bumbling dragon around anymore did upset him.

Also chuckling a little at that pronunciation.]

There's no 's'. But it is a weird name...

[Pause.]

Oh, you know. Nothing major. Cold. [Understating that quite a bit, but...essentially it was the truth.] It's been going around, too, so it's not like it's a case of 'Gee, look at that boy. So small, so feeble! No wonder he got sick.'