Right to property

My maternal grand father had five children -four daughters and a son. He had inherited an ancestral property. My mother, one of the daughters, expired in 1952 when I was one year old. And as an infant I was taken care of by my paternal grand mother. After the death of my grand mother as we were children, one of my mother's elder sister came to stay with us   My uncle was mentally unsound and had no family. In 1970 my uncle fell ill and was hospitalized and expired at General Hospital. I used to visit and attend to his needs while in hospital and as he had no children I was required to perform his last rites. And since then I have been performing the annual sradda for the last nearly half a century (It is said that as per our caste tradition, one who performs the last rites of a person has the right to property of the deceased). Am I, therefore, entitled to the share of my uncle in the property.   After the death of my elder brother in early 90s and father in 1993, my mother's sister continued to stay with my sister in law for some time. She was suffering from cataracts. I had her operated in a free eye camp conducted by Lions Club sometime in 1994. As I was employed in Msharadhtra, it was difficult for me to take her with me and so I had her lodged with one of my and sisters with whom she lived till her end in 1999.   Some time in 1998-1999, my sister visited the property and had duplicate title document made with local help. Showing my mother and mother's sister as the only heirs and got my mother's sister's right in her name.  I have not seen the document.   Now she says she has right to the half portion of my mother's sisters and also a portion from my mother's.   Do i have right to my uncles (whos last right and annual functions i perform)? Can the title she got made be challenged?   Pl give an opinion. Tks.   NARAYANAN Palakkad, Kerala