Can first wife avail husband's pension benefits or maintenance

Hii, my mother is first and legal wife of my father. My father remarried to another before 25years having one son and two daughters. Now my father living in Bhubaneswar with his second wife. My father was employed in Indian railway and retired August 2017. My father never give any financial and social assistance to my mother. And my mother lives in inlaws house and no contact with my father since 25 years. Very surprisingly we got to know that family pension and other spouse related facilities can avail my stepmother due to her name is in respective documents. I want to know is it possible for my mother get maintenance charge and spouse entitlement like family pension etc... My father got job after 5year of marriage to my mother.