Harassment by daughter law

Hi, I have two brothers and both got married. My second younger brother got married in 2016 and SIL started fighting with mom from the first month onwards. She always listens to her parents and tortures my mom. She even said that either of us has to stay in the house, but not both. My mom actually she struggled a lot in her life to grew up us and so she ignored their egoistic mentality always. When my SIL got conceived, my mom was so happy as the new arrival will be the first child of our house and helped her in all the possible ways including clearing this girls vomit and taking her to hospital regularly. That time her parents were not ready to come and help for even few days also. Then after delivery due to my brother's job they have relocated to my place. Problems started to my mother and brother from then. SIL's mother has to tell what the baby has to eat and my brother and mom doesn't have any rights on the baby. I m not allowed to feed the baby with some sweet or prasad. If the baby starts crying for something in the night she blames that we have given her some thing wrong. So we stopped giving anything to the baby even if she cries for that, for example she likes water melon a lot but we are not allowed to give her that as it can cause stomach ache to her. If her parents gives the same she will be saying it proudly that her father got a watermelon for his granddaughter as she likes it very much. In total our affection towards the baby is being suppressed. To get rid of all these nonsense my brother started working for extra time. Then she started saying see baby no one likes you, everybody likes money only. New story is my mom has some work in the native and she went for few says, SIL irritated my brother saying when my mom will come back as she is incapable of doing her regular tasks even if brother does most of the chores. Then my brother faught with my mom and called her here. She was ok for 3 days again for no reason started scolding my mom when my brother is not at home. My mom at the age if 56 will be doing all the work at home like cooking, cleaning if required and taking the baby down for playing. Still this girl is not satisfied. Last week my husband got a call from her father saying that my brother manhandled the girl based on my mom complaint and he(her father) will lodge a police complaint against my mom and brother. We went running and when we saw the situation was different, what we understood is that my brother didn't get up and give her phone when she asked for it and they had some argument for sometime. The manhandling thing happened 20 days before when my mom is not in town and that too both of them tried to man handle each other. Now their intention is to send my mom back. Even my mom don't like to be here but this time we don't want to send her back as similar thing happened earlier also. Pls let us know how can we fight legally for my mom, she is financially strong enough and not dependent on anybody.