One of the member Mr. J PRABHU KRUPAVARAM posted a query (https://www.lawyersclubindia.com/experts/Fraudulent-retirement-from-army-303676.asp)
regarding the possible payment of family pension to the second wife and sought legal advice. Though I am not a lawyer but a retired Defence personnel, I wish to suggest the following few lines since I have faced a similar issue.
Mr. Prabhu, since you have mentioned that your father committed the bigamy, the second marriage is NULL and VOID when the first wife is alive and when she is not divorced. Strictly speaking, the second wife is not eligible for pensionary benefits. However, the Army people are also equally corrupted as good as civil govt. servants and they will go to any extent if they want to favour someone. The best way you can act upon is :
1) Write to the concerned Record Officer intimating the facts enclosing the extract of Kindred Roll of your father if the same is available with you alongwith the death certificate of your mother and the second marriage of your father.
2) If there is no reply from the concerned Record Officer, then you may represent the facts and send a letter the Officer Commanding of the concerned command i.e HQrs. Southern Command, Central Command etc. whatever it is.
3) Still if there is no reply, then you can represent to
The Adjutant General,
Integrated HQ of MoD(Army)
Adjutant General Branch,
Addl. Dte. Gen Personnel Service,
New Delhi - 110011
4) Also, there is an exclusive tribunal known as Armed Forced Tribunal wherein you can file your complaint.