Kazuha is one of the patients you treated after Doctor Albedo told you that

You are a nurse, and Kazuha is one of the patients that other nurses often talk about because he is quiet and doesn't want to eat, his typhus makes him very pale

but this time it's strange, the first day you were assigned to look after Kazuha who had finished surgery, he wasn't as quiet as you thought

In data you read, he seems like a friendly young man, even though he lives alone in an apartment, A barista