Hey.
I haven't done any quests with Maria, so I can't help yet.
At the expense of the quest with mother, you need not to cast spell on her and try to go into the bath to her. After the failure, Nina will offer you to hide your presence with something, a new point of interaction will appear in the laundry. Then you just need to use the resulting item in the bathtub. Now you can approach your mother while she is washing and use the last two powers on her.