Pension To 2nd Wife

Sir my mother is 2nd wife of my father. My father was a teacher. He nomitate my mother in service book. After the death of my father, my both mother applied for pension. After spending three year in court they compromise on that 1st wife will get pension and second will get g.p.f/fund etc. But before 1st wife get pension she died. Now my mother applied for pension. Two days ago we recieved a latter that we need succession certificate of my mother for pension approval. My question is that,is my mother eligible for succession certificate /pension