Ownership of mother's Encestrol property after her death

Hello Sir/Madam, Mother has acquired a ancestral property (House) from his father in-law and husband (as per sale deed) in 1994. The sale deed is on the name of mother as purchaser signed by both her father-in-law and husband as seller. Mother died on 1995 due to illness. Mother has 3 legal children's, 2 sons and 1 daughter. All 3 are married and having 2 kids each. Father married 2nd time with 2nd wife in 2001 and having one daughter. At present daughter from 2nd wife is become Major 19 years old. The property patta which was applied and done in year 2002 came out on the name of Father and Father's 2nd wife as Joint holder. All 3 legal children's from 1st wife (mother) were Major during 2002 when property Patta applied. P.S = The patta was applied without any consent from all 3 legal childrens from Mother (father's 1st wife) Question - Who should be the legal heirs of the Mother's ancestral property. How come my father and father's 2nd wife name came in patta. Why 3 legal sons and daughter name is excluded in patta. I sense kind of furgery.