Deceased father's pension and house

I am now 40 years old and still unmarried and have been bed ridden due to my sickness. I have no jobs now and no money my house rent. I was running my boutique but it went on loss, to survive i started working in call centers. I have a brother few years older then me and was supporting paying the house but now even he is jobless due to his health problem. I have debts to clear and now i am clueless what to do, confused and going through depression laying on bed adviced to take bed rest for 2 months due to slip disc. My fsther was CMO at GTB delhi and got retired around 2001 and passed away of cancer and ever since my step mother has been taking the pension and taken our father's house. We don't know whether she has legally registered the house in my name as she use to hate(me and my brother) and use always fight physically hurting my dad demaning money and propery. She has two sons from her previous husband and no children from our dad.from 8 years she taken the pension and the house in delhi. I tried many times to claim but all my friends and known people adviced me not to claim and to leave her alone, i felt hopeless and kept silence all these years thinking that my step will kind enough and will help me financially as she knows that i am struggling but she never asked. My our mother passed away in 2016 here in delhi, i did try to the pension for her after my father's death but we failed as there no marriege certificate or proof. My father had married my mother in Arunachal pradesh in village panchayat and now when we needed those witness are also passed long time back. My father who actually married four women, the first two wives were married legally and the second were not as they just eloped with my father though they were already married. My mother is the second wife, so the first and second(our mother) they both are no more, the wife went back to her hometown after realised and that about 30 years back so she has no connection with us ever since then. Now the fourth step mother who enjoying our father'pension and the property. Now i plead and request humbly is there any way or do i have chance that i can a part of my father's property and the pension? Kindly advice plz. Many thanks.