Settlement deed

My father expired in 1982, we are two childrens for our Parents. My mother is a retired state govt staff (retired in 2012 Jan). I got married in 2009 Jan and my younger brother got married in 2011 October, after my marriage myself, my husband, my mother and my younger brother we four are living together in my mother's home which was purchased in the name of my mother and her younger sister in the year 1994. Nominee was not mentioned in this purchase deed. My mother's sister didn't have good relationship with my mother and filed a case in 1997 or 1998, that time I was studying in 11th standard and my brother was studying 9th std, my mom went for settlement of 8.5lakhs to her sister in the year 2015 and the property was registered in my mother's name. After my brother's wedding, his wife's family members doesn't liked me to stay along with my mother after my marriage, they want me to go out of my mother's home,even no problem among us so went out. Inthe year 2013 my mother was operated for Breast Cancer in Apollo, Chennai and she is a Diabetic from 2007 onwards, With her own savings she got treated for pre and post surgery and beared all the surgery cost too. My brother managed to get a settlement deed from my mother in the year 2014 and again after a few months later from the day my mother settled money for her sister. So twice my brother got a settlement deed from my mother and both are got registered. These two incidents I am not aware of it, without my knowledge he has taken the property from my mother through registering in his name. After taking all the retirement money and her property, my brother and his wife both started showing their true colour to my mother. She has mentally harrased by using filthy words and ill-treated my mother. Her routine work is waking up at 4.30 or 5am to cook food, washing clothes, cleaning vessels, moping all the rooms etc., Her daughter in law sleep till 9am, after pack the food and goes to her mother's house. Not taking my mother to any doctor's consultation, heavy work not considered her age and health factor, so she has become very lean. My brother didn't allow my mother to speak with me or to any of her friends by threating her that they (my brother and his wife) will committe suicide and in the suicide note dey will mention my mother is the only reason. So she got afraid and doing all the works to them. She was not in communication with me for the past 5 years. But now she came and spoke to me and said all these details and she also told me that they both threatened and taken the property too. Now the EB, Property tax, water tax and other taxes are in my mother's name, Patta is in the name of previous house owner who sold the property to my mother. In 2015, after given the settlement deed to my brother, he mortgage the property and registered it, my mother is the guarantor. Now vat shall my mother should do?? And vat shall i do??