Property issue with relatives.

I hail from Kolkata however due to ailment of my sister we moved to vellore, Tamil Nadu around 18 years back. She was treated in CMC, vellore. Since then, we are settled in vellore. In between this time, my grandmother expired(my grandfather had expired prior to this). My father had three brothers and two sisters. My father being eldest of all brothers and second eldest to a daughter. The daughter who got married and settled in Delhi is the eldest of all. Our family separated due to issues amongst brothers and we moved out of our paternal house 10 years prior to moving to vellore for treatment. My father visited Kolkata on my grandmother's funeral and took care of the rituals. However, when the assets were being distributed, they didn't allow my father's indulgence and he was thrown out by the only brother alive by that time, the three sisters and their husbands with only Rs. 1600 handed over to him as a part of his mother's asset. However, my grandmother had good amount of gold jewels and silver utensils in her custody. We heard that all this asset was passed on to the eldest sister who stays in Delhi(she confirms this). Neither the widow of one of my other uncle nor my father got any of these assets. Now even the other uncle who was indulged in this arrangement is dead. Though the elder sister confirms that she has the custody of the jewels, she declares it to be scanty. However, my father knows that either the jewels were either sold or still in her custody but she is lying. Also, the papers of the paternal house in Kolkata are not given to my father or the widow. With all the brothers dead, I believe my father and the window of his brother should have the custody of the house. The eldest daughter in the family is a big fraud. Long time back,she and her husband enticed my father to purchase a land in Delhi, they took the money from him and got this land purchased in their name. Due to blood relation, my father didn't take a measure to resolve this issue. We have been cheated by these people time and again. There has also been an incidence of physical assault to my mother by the eldest daughter of the family. My queries are as below: 1. Is there a way to recover the gold and silver from the eldest daughter of the family? Are we not the legal heir of the property of our grandparents? 2. Out of these three sisters one is already dead and the other two are is accused in criminal case(dowry) and the eldest daughter is guilty in property case(property fraud) with a third party. Can this make our case strong? 3. My father was the breadwinner and the only financial contributor to my grandparents prior to separation. As there is no will therefore is he not entitled to the assets and property of my grandparents? 4. My sister is a handicap now. We are trying to obtain our share so that we can safeguard her future. Our financial condition has become unstable to due relocation to vellore from Kolkata where my father was working. Shall the law assist us? Please assist with your suggestion so as to how we can pursue this fight. My family needs help and relief from these greedy and fraud people.