So my daughter is 2 & my sister is 3 but my sister is autistic. Whenever my mom takes

My daughter for a few she always yells at her, telling her to share with my sister, be nice, don’t do this, don’t do that, and basically everything in this house is my sisters.. give ___ back her toys, no those are ____ toys... don’t drink ____ juice. No that’s _____ Ipad etc but when it comes to my sister if my daughter takes a toy she’ll yell at her and say No give it back to her, if my sister hits my daughter it’s ohh she doesn’t understand ( which I get ) if my daughter does it, oh why you hitting her... don’t hit her.... like it’s always something. She treats my daughter wrong sometimes and I don’t like it, I understand my sister has autism but she needs to treat them both the same, you know with a few exceptions because of her disability, am I wrong for feeling like she treats my daughter wrong sometimes?