Welcome! Thank you for your question.
What Bank of America should be requiring is a death certificate for your father.
This would be enough to make you and your two sisters owners.
Where is gets complex is that to have the account divided up upon your sister's death, your sister is going to have to be court appointed as executor of your deceased sister's estate
or get an affidavit of distribution. Either one of these will have to be obtained from the probate
court in California. Here is a great website that summaries her steps in the probate process in California. http://www.courts.ca.gov/8865.htm
Since the account was not POD prior to your sister's death, part is going to have to go through her probate estate to provide access to the who account.
I cannot provide you with legal advise. I have provided you with information about the law related to your question. My answer, and any information that you find online, should not take the place of having a consultation with a lawyer in your area to advise you regarding your specific issues.
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