Protection against mental torture

Hello, I'm Subhranil Roy from Howrah. I need some advice. I haven't much idea about property related laws. My maternal grand father's house locates in Kolkata. He passed away 8 years ago. He had 2 daughter and 1 son. He didn't make any will. His small daughter ( she was unmarried) died in 2012. So, now his house belongs to my maternal grand mother, my mom & my maternal uncle . Grand-ma lives in the ground of that house. And maternal uncle also lives in the 1st floor with his wife and daughter of the same house. Recently my maternal grand mother want to give 50% of her portion to my mom. As per her wish, registration is done in presence of a register. My mother want to talk to his brother to make a clear demarcation of the property. But my maternal uncle didn't want to negotiate with my mom as he claims whole property. After registration of grand mother's 50% to my mom's name, he is furious. Now he starts throwing slang languages & also threatens my mom not to enter in that house. My mom & my maternal grand mother are extremely confused and afraid. My maternal uncle is mentally torturing my mom & my maternal grand mother. Here I want to do something to secure my mom & her mother. So, I want to know that, can I take some legal steps against my maternal uncle for his mental torture or file a complain in local police station against my maternal uncle? Please let me know what can I do for my mom. I feel very much restless. But I want to do everything in a proper legal way. I'm waiting for your precious advice. Your sincerely, Subhranil Roy