@Malaxme but then why would she say it's all a lie? Is she saying he is just using her or something, because he has protected her as a sworn brother so that is not a lie, and no way a teenage high school girl unaffiliated with gangs and such would be thought to have a sworn brother, as it is old fashion in modern society and only kept up by traditional yakuza and triads, and family members in mafia
Also the teacher didn't seem to call out for him not being a blood relative, or guardian since most schools don't allow non relatives in.