Christian husband right in first wife property after remarriage

Hi we are Christians from Andhra Pradesh. My mother bought place in 1983 and died without writing will in 1991.At that time my brother is 21 years, I am 14 and my younger sister is 12 (3 children- one boy and 2 girls). My brother and I got married and my younger sister is spinster. Till today my mother property is not distributed. My father had a daughter from illegal affair with other woman when my mother was alive and that girl died in 2009. So now we are 3 children to him. My father married again 6 months after my mother’s death. My step mother has 2 children as a widow from her first husband and nobody from my father. My father died in 2015 leaving a will that his 1/3 rd part from my mother property go to his second wife. My father worked in police department. She is getting pension. I would like to know whether my step mother gets share from my mother’s property as my father left will on her name. She sent lawyer notice to give 1/3 part of my mother property. Which laws giving right to a man from first wife property ,who is deceptive during her life time.