Once the bank knows that a depositor has died, they become very strict with policies (especially if you don't know anyone from the inside). It's because they don't want it to be their asses on the line more than anything else, really.
Banks require the same general documents before releasing funds from a dead depositor's account, and these are:
1. Certified true copy of depositor's death certificate
2. Certified true copies of heir/s' birth certificates and/or marriage contracts
3. Letter from the heirs listing the details of the deceased depositor's account/s and stating that they are the legal claimants of the account/s
4. Proof of settlement of the estate, whether judicially or extra-judicially
Number 4 is where it gets bloody. If you settle judicially, the bank will then only require a court order, but that means that you have to file the whole settlement of estate with the court.
If you settle extra-judicially -- meaning the family can agree to divide the deceased's estate amongst themselves -- then that's good. But you are in for a lot of work. Filing the
extrajudicial settlement is a monster in its own. You then have to provide original or certified true copies of:
A. The extrajudicial settlement itself
B. Affidavit of publication of the extrajudicial settlement and partition of the estate in a newspaper once a week for three consecutive weeks
C. BIR's certification of payment or clearance of estate tax -- expect to wait up to a year for this
D. Registration with Register of Deeds of extrajudicial settlement -- this adds another few months of waiting
E. Heir's bond -- you purchase this from a non-life insurance company. It's insurance for the bank in case there will be other claimants who come after the deceased's accounts after they've released the funds
F. Affidavit of quitclaim with indemnity undertaking -- the bank makes the heirs sign this form, which basically says that they're washing their hands clean in case claimants other than the legal heirs come out of the woodwork and go after the deceased's accounts
More problems and paperwork arise if any of the heirs are minors, if a few years have passed since the death of the depositor (bigger BIR penalties will apply), and, of course, if the heirs cannot agree on how the deceased's estate will be divided.
This is old, but I find this article to still be relevant today:
What to Do When Somebody Dies POINT OF LAW By POINT OF LAW by Teresita J. Herbosa