Will yo drive to Tokyo to collect your son? Or perhaps he can hire a car and drive himself? Or will he have to hotel quarantine for 14 days?

At one time there was a flight from Tokyo to Nagoya that qualified as an "international," - IIRC, passengers all connected from international flights without clearing customs and immigration in Tokyo. It would make sense to operate such services to KIX, FUK, CTS to make life a little easier for people who want to return to the regions - but I don't suppose that's on the cards.