Ancestral vs Self acquired property

My father and mother brought some properties on their own so as to make me and my sister doctor. He's brother is claiming shares in my father self acquired property.Many years ago father and his brother got ancestral property from grandfather and today being title holder of that respectively.Grandfather is alive but my father died in 2014 .In 2021 my uncle has sued a file in court stating that my father self own property is also ancestral property and wants shares in that .Plz help me for next procedure.