It edges on grooming, but in reality Minoru never lead Fuutarou on. He tried to push Fuutarou away but Fuutarou was whipped for his Minoru-san. I don't really like love stories between parental/guardian figure and their dependent, because it just seems incestual and groomy, but this is one of the few that's acceptable.
Gohoubi wa Shitsuke no Ato