Regarding Bank laws

So long as the Divorce was not granted before the death of the husband, the relationship of husband and wife remains.  Therefore, the Bank is absolutely in the wrong in denying operation of the account by the Wife.

In addition, ask the wife to withdraw the divorce petition, as her husband has already expired, and there will be no use in pursuing the divorce petition.  (This will also effectively answer the bank's objection that divorce petition is pending.  Once the petition is withdrawn, the bank's objection also should go.)  This does not mean, that the bank is right in denying the wife from operating the joint account.