Apparently you don't understand a god damn thing. The father most likely couldn't send letters and trusted a family to watch her. They were doing everything they can to keep her safe, the main family were not the ones who abused her, sure the grandfather could have checked in and tried a different approach but he couldn't be loving towards her otherwise that would compromise her safety. Her siblings do love her, just awkward at showing it because they are kids, the eldest brother left to protect her by sacrificing himself to keep the Queen at bay. This family is honestly not the worse I have read. Could they have done it differently? Yes, but they did what they have to do until Rie can use her ability.
Neglect is a form of abuse. I'm frustrated that the ABUSE this kid went through for ten years is being brushed under the rug because of "oopie doopie, excuses and circumstances"
The only one you should turn that blame to is the Grandfather for not doing enough. The father and her siblings didn't neglect her, there are good servants who do enjoy tending to her. She may have been ten when she died, but ten year old do NOT have the emotional intelligence, or at least enough of it, to want revenge against her family, she loves her family and want to protect it.
Also, this is not "oopsies, excuses and circumstances," if you don't like it, get the fuck out.
There is no karma for the neglect that happened to MC. All the characters just say "oops, sorry there were circumstances," and then they're just magically forgiven. Nah forget that. 10 years of neglect will traumatize ANY child. You CAN'T tell me that she regresses and suddenly holds no grudge to anyone? It is not a child's responsibility to heal the relationships of her family, THAT IS THE ADULTS JOBS! The grandfather can suck it for all I care. "Oh but I couldn't approach her in order to keep her safe," HOGWASH! SEND PEOPLE WHO CAN TAKE CARE OF HER THEN. "Oh father is at some random border and can't come home," DID HE NOT THINK TO WRITE TO HIS FAMILY AND BOTHER THEM ABOUT MAKING SURE HIS LITERAL INFANT DAUGHTER WAS OKAY?
In conclusion this story treats abuse like a joke and I can't stand it. Author can kick rocks for all I care.