Query on Properties division after my father and grandfather death.

Hi, I am Krishna from Srikakulam, Andhra Pradesh. My paternal grandfather owns few lands and he is passed away. My grandfather have one daughter who is unmarried and mute. I lost my father 12 years ago who is only son to my grandfather. As recently my grandfather expired, his daughters pitched in and asking us to register few properties for their mute sister. And they are even warned us to file complaint. I want your advice on what will happen if they file a case. Few things to mention 1. Mute daughter has a land on her name given by my grandfather when he was alive. 2. There is one property on the name my grandmother which now the daughters are claiming theirs. Please advise on this.