Father left from us (10years ago) now came after his wife death and demanding for family pension or else he is asking job

You may give all the details of his deserting your mom and the family and his never fulfilling  his responsibility as father and husband. His marriage to another lady without taking divorce from your mother amounts to bigamy. All these may be reported with possible proof of his misbehaviour, preferably signed by all children addressed to the competent authority of the employer praying  not to give pension or job to him. The employer surely shall take a suitable decision.

Family pension and compassionate ground appointments are meant for those who take responsibility of the family people  but not to those who desert family and claim only the benefits.

Who is receiving Family Pension at present? Has anyone, i.e.the son or the daughter, applied for compassionate appointment?

Have you applied? What about gratuity, leave encashment, GPF etc? Had the mother furnished family particulars to the Office? Please ascertain.