I'm guessing the dad used to be shota (lol), they got married but as growth spurt kicks in he turn into.. let's say very burly and manly man which shock the mom who's now realizing a boy could physically turn 180° is a scary thing.
If she likes him that much, why is he still wearing a mask? I mean they have 3 daughters so it's either
1, she's now afraid due to his old ass fat ass face
Or
She would go full on maximum tiger in heat mode if she saw his face