Threating For Filing a Fake Dowry Case against my whole family

My brother got engaged to this woman. He did 'Jaymal' too in engagement. We protested that time, but more or less senior people stop us from making it an issue. Then afterwards, after sometimes we found out that girl abuses his brother. She does this over the phone with my elder brother. Basically, she said that her brother has come, and now she had to prepare tea for this motherf***er. My brother rebuked her. She said it is instinctive for her. A few days later she again read that over phone 'motherf***er has come.' She abuses her real brother who is elder to her. My brother rebuked her again and demanded her to not abuse him further. A few days later, she said to him that she wants my brother to depart the house after the marriage and settle somewhere else after marriage. My brother questioned her about the intellect. She replied that she had seen a picture on the internet. In that picture show she said that father sexually abuses her daughter in law. She said that as your brother is working, and you are also working and also your mother had died. There will be no one will allowed in the home, but she and my father. Who might abuse her. This was too much for my brother and he went straight to her aunt (Chachi). He literally told her everything. She brought this into my father consideration. My father incapable of traveling. He sends me and my uncle's son to complain about her through the man who brought relationship. Later, some time we ask them to come to our place. But they didn't correspond. Right away they started threatening us that they will lodge a case against us. They are threatening us to file a dowry case against my sister who is doing PhD from IIT Roorkee, me, my brothers (uncle's son) & my father. We even haven't thought of ruining the relationship that time. But at once after his continuing threats to our various family members, we are afraid that we are in big trouble. My family already fighting another case in which my mother was killed by some goons on the eve of Deepwali. She had an operation a month ago. She was having problems breathing. She got out to complain to people who were blasting big cracker on the wall of my house. We had tried to block her, but she said that she will die of this smoke. My whole household was filled with smoke. They are also a bunch of goons. They pushed and get her. When we protested we also got crushed. We telephone the police and ambulance and she died on the way to second referred hospital. Right in front of my eyes. Yet, those criminals managed to fudge the PM report which said that she died 3-4 days before Deepwali. I am the one who had thrown her body at PM house. She had dropped dead in front of me. This case is influenced by some powerful political leaders. We are so troubled already and this is taking place.