Does second wife of my father has legal right to ask share in my ancestral property

My father died in April 2020 and after 6 months of his death surprisingly I received a legal notice asking for share in my ancestral property from a lady claiming to be his legally wedded wife. My mother or first of wife of my father died in 1997 and my father retired in 2009 he is a central government employee. My father sold his share from our ancestral property in 2018 november. Does his second wife (claiming to be) has any right to ask 50% share from my father's share of ancestral property or from the sale consideration? As the sale registration done by my father and myself jointly to buyer in 2018. Hindu marriage act applies to my religion. And the second wife is also claiming his pension to be disbursed on her name post his demise in april 2020. Questions: 1. She is claiming her share of 50% share from sale consideration of property which my father sold in 2018? 2. I have second ancestral property which, the second wife is asking to give 50% share out of it, how is that possible? 3. Can the second wife after demise of my father claiming in front of everyone that she is legally wedded wife of my father, what will be my stand? How can I defend myself out of this situation?