I'm guessing it's a cultural thing cause this isn't the first manga I've seen this happen in
where i live it’s a pretty big deal to have close relations with a student and their family tbh, it’s pretty looked down upon
It's necessarily abt it being romantic tho. In a lot of countries is a big issue for other parents that a teacher has some sort of relationship w the parents of a specific student bc it can lead to favoritism.
In mine is not that important unless they're blood related, like if you're a teacher and have a kid/nephew/niece/step kid at the school you work you CAN'T be their teacher bc (even if you say wouldn't) there's no guarantee you won't be biased
they are making such a big deal out of seeing students outside of work and like having a friend. also cant the mc just say "we are high school friends and ive always helped out with the kid bc we are buddies" (even if the last part is a lie) like most ppl arent going to assume someones relationship is romantic and teachers have kids who are in their class and it doesnt matter just say your'e his uncle figure for public reason and carry on with life
i love the detail to hinata saying "where is your dad" and he's friends being like its probs his mom.