How strong am i

Hello sir, My father's small sister was married on 1972,On 1974 my grand father given one acre of land as pasupu/kumkuma and he sold half acre land to clear the bank loan for her marriage only. My father's small sister sold that one acre to other person, we have the copy of registration document(land given to my father's small sister) and Land received document copy from other person. My father's big sister is favour to us, that she is ready to give statement that we already given her part in assets and i also received my part from assets, her behaviour is not good she always looks for easy money. My father's Small sister filed a case against us, she is saying that all the assets are controlling by my brother as joint assets and expired person my father was not allocated anything to anybody and my brother is enjoying annuity benefits, so we are requesting you to allocate our part to us and to my big sister. My father's big sister is saying that my father given their part to me and my sister in the form of money and land, remaining land belongs to my brother nobody(i and my sister) dont have any right on it Please tell me your opinion about this case.