Children's book. Main character's name is AVA(or someone in the book). I have looked into flowers in the attic and I don't think it is those books. She has a mean grandmother who washes her with a scouring pad if she wets the bed and puts her in hot water. Gives her enemas and a lot of crazy abusive stuff. I think in the end her mother was putting them through this to get their inheritance. Maybe their dad died?