She Called My Daughter Retarded!

I can not believe my own sister would say this! My daughter is 14 and autistic. She isn't very good in social situations. She also wets her bed. Which is why she used Goodnites at night. My sister has a daughter who is 16 and is just mean. I hate going to see her because she bullies my daughter and my poor girl is too shy to stand up for herself. I was helping my sister with some personal stuff and we stayed the night. My daughter forgot to wear her Goodnites and had an accident on my niece's bed. My sister's daughter then HIT mine! I understand she was upset but she had no right to HIT her. I went to my sister about it and she looks super annoyed then goes "It's not our fault your kids fucking retarded!" I couldn't believe she would say that. I told her to never say that again and she continues saying "You decided to raise a retarded baby" and all this stuff trying to defend her daughter hitting my child. I left with my daughter. She was so upset and crying. Autism does not equal stupid. I can't believe she would say that no only to my face but in front of my daughter!