Y'know, ever since reading the Sumi spinoff, I've been reevaluating Kazuya as a character. I think this entire time he's just been trying his best and putting on a brave face despite the circumstances— if we didn't see every little thought bubble in his head it'd probably be a lot more bearable.
That being said, I mean, why not ask Chizuru to introduce him to people? He's in school for business administration, talking with a couple of those "fat guys" could net him an early job or internship for some experience. Think about your future, man!