Looking for my mother's right

Hi Experts, I am a Hindu by birth and later converted to Christianity for marriage. I am a single child of my parents. My father is 59 years old, and we have realized that he is in relationship with a 31 year old woman (SM). Since 2015 Dec my mother( 53 years )is suffering from a severe disease and she is on bed. Our assumption is she is behind my fathers wealth and my father is happily spending on her. Though he is not confronting this. In another 2 months I am planning to get my mother to my house and she will stay with me and my husband. Now my questions are: 1. By bringing my mother to my house, am i taking her rights on the house and wealth of my father's?? or else should I convince my mother to take divorce (which I dont want at all) 2. Before bringing my mother, should we confront my father and SM about their relation?? We dont have a valid proof but we are 100% sure about their relation. Should we go for a detective?? 3.As my father will retire in Jan 2018, I am afraid that SM will take my dad's money and then do ANYTHING to my dad. I have no interest in money or property but my mother is not ready to give her house, Jewells and money and above all the RIGHT OF A WIFE.What can be done here?? He is a gazetted officer and will get a huge amount on his retirement. 4. We got to know that SM's husband is impotent and she is taking my father's help to conceive.What if a baby is born, that will be my father's illegal child. 5.How can I make sure that I should get the property of my dad or will my mother has any rigth on property? 6. It is difficult for me to ask but i am doing, what if my mother passes away and dad marries SM or what if my dad passes away without writing a WILL. It is a very difficult situation for me as I am his only daughter and he has always loved me but unfortunately he is strongly influenced by this woman and torturing my mother as she being his wife can sense that their is someone else in his life. I dont want to file any complaint, but if needed i will. Also I wanted to know is there any way I can complain and he should not get the retirement money. It is just because we think this SM will take everything. Should we hire detective but we dont want father to get caught and later his job will suffer. Thank your giving your time. Looking forward for the advice. Regards SS