I keep wondering can he actually just quit his house and leg it to Sensei if he really wants to? Pretty sure his mom will stalk him to school or some other shit.
I feel like the MC has now got double the creeps, a yandere mom and sensei.
I find it a little sad Nagi's original fate was to end up as a caretaker. I hate those kind of convinient marriages where you're just buying a fucking servant/helper. Hire One.