My parent have been alleged illgeally and life threatened!

Hello Sir, It's been awful to see my parent specially my mother being alleged illegally and received life threat from my sister-in-law's mother and sister. It was about 2am in morning, my sister-in-law cut her hand to put blame on my parent. Meanwhile, my father called her family, her mother and sister threatened to kill my parent and burn. My sister-in-law never obeyed any domestic norms, she and her family made my mother the servant at own house. Once my father had to clean her room on regular basis. My sister-in-law was manipulating every word of mother and explained as torture to her family. She even exploited my elder brother. My mother was mentally tortured extremely by all of them. I have a beautiful, cute 1and1/2yrs old niece i.e daughter of my elder brother and sister-in-law. She never take care of her nicely. Sometime she bits her too. We usually find her spending maximum time of a day calling someone or operating mobile device. Foremost we found her very unnatural to life. She is very aggressive minded and freaked. She wants everything to be in favor of her. I am very scared about my parent's lives, my elder brother and their daughter's life. So, I am seeking for legal advice and guidance and also I have a question... Can my mother lodge 498A against my sister-in-laws and her in-laws? N.B: she had cut her hand multiple time in past and we found her loving blood oozing out from body.