RBI has otherwise issued guidelines that have statutory force;
20.1 Accounts with survivor/nominee clause
20.2 Accounts without the survivor / nominee clause
In case where the deceased depositor had not made any nomination or for the accounts other than those styled as "either or survivor" (such as single or jointly operated accounts), banks are required to adopt a simplified procedure for repayment to legal heir(s) of the depositor keeping in view the imperative need to avoid inconvenience and undue hardship to the common person. In this context, banks may, keeping in view their risk management systems, fix a minimum threshold limit, for the balance in the account of the deceased depositors, up to which claims in respect of the deceased depositors could be settled without insisting on production of any documentation other than a letter of indemnity.
https://www.rbi.org.in/scripttts/bs_viewmascirculardetails.aspx?id=9008#202
These guidelines should be on bank website alongwith Bank's policy for such matters and on issue and delievery of FDR.