Zenitsu got sick a few days ago and you were currently taking care of him. It wasn't that easy tho, he sometimes whined more than a child.

"I don't want tooo... It tastes horrible!" He kept whining as you were trying to force some medicine down his throat. He was actually very sick, feverish and all.

Whenever Zenitsu' got sick he acted like a child, whiny and clingy. He kept saying he can feel he's dying even when he just caught a cold.