@Fushiginiku Disagree ok that only maid got physically abused while MC wasn't as shouldn't be any abuse in first place, and MC was emotionally and verbally abused at times which can wound deeper than physical injuries. Such as the extremely strict and long practice times on the piano. Granted she's extremely talented as a result but has low self-esteem and few good memories with her grandmother as a result.
Agree that MC has experience due to her grandmother. However, there is a difference between someone who has trouble or can't accept reality over delusions due to brain damage caused by injury or old age which is untreatable and uncurable, and someone stuck in 8th grader syndrome who refuses to accept reality by choice. The grandmother was in declining health, was only going to get worse no matter what was done and never better, and the shock of abruptly forcing reality on her could kill her. The heroine, however, is young, in good health, doesn't have any physical or mental problems hindering treatment, is choosing to believe things are like a game she played while refusing to accept the differences in reality, and enabling her is just going to allow her to trouble the MC further. She's already dirtied a school uniform MC had no replacement for, assaulted MC verbally and physically, and causing people to believe she's a wild child with no maturity or tact.