Grandaughter with SPD

i have a 5 year old grandaughter who i believe has spd she has had symtoms for several years. her mother and father refuse to even consider getting her diagnosed or treatment. i feel so sorry for her and try and do what i can to help her. example she has a real problems with shoes hurt her feet. her parents refuse to believe she has pain and force her to wear the shoes saying she is just being difficult and picky she screams when they try and give her a shower saying they burned her with the hot water. i know thats not true but that is her perception . any advice i would appreciate.