Obviously the mom has some devious plan cooking but what if Shigeru does too. What if he does remember everything he's just pretending not to most likely out of fear.
Also did anyone else peep that everyone look horrified when Seiko spoke. Her aura is just that off putting.
It's sweet how devoted smiling auntie was to staying with Shigeru that whole time. She's not the best aunt, but clearly went through a lot as a mother offscreen.