Individual — encashment on closure

Address:

600020

I possess 3 gius 1989 (Ii) certs of600 units
Cert no h89316715
H89316717
H89316737 for 600 units the holder k gopalachary is no more and i am one of the two successive nominees.
Should i produce death certificate of the holder?
Can one of the nominees alone make the claim?
I approached the chennai guindy office but was told as it is old units they need time to search the records. It is more than 15 days and hence this communication

Kindly let me know how to claim the proceeds
Sarayu lakshmi