Pension amount rights to wife

Respected Sir / madam, Due to a harsh circumstances / argument, my father (ex navy) had to leave house 1 week ago. Already, for past couple of months, he didnt give the pension amount to family. Now he is threatening us that he will never give the amount as it belongs to him. Since he left, he is asking for his pension related document from my mom forcefully. 1. Is there a chance for him to remove my mom name from the pension and nominate some other person (we suspect him to have an illegal affair) 2. To what extent my mom has the rights over the pension amount. 3. Can my mom legally take this forward to avoid any misuse. Please guide us. We are holding the documents until this clarity.