
Underage in Japan is 20(or so I have seen from movies and manga) so this could be less creepy than it seems. I googled it and it also said 20.

Okay so the thing is being underage and being a minor are two different things. While the consensus is that 20 means you’re underage in Japan (can’t drink), what constitutes being a minor changes depending on your prefecture. In some places it’s 16 and in some places it’s 18. Etc. it goes to say tho that if he’s a high school third year he is 18. And if he’s a high school second year he is 17. I don’t understand why he’d be 20 in senior high. Most ppl are either 18 or 19. Maybe he started late or smth. I do think everyone is overreacting tho. He’s literally about to graduate.
Where is his wife? She hasn't been mentioned since they tried to separate them