Is It Identity Theft to Use Dead Person's Credit Cards and Open New Ones

My question involves criminal law for the state of: New Jersey My brother, the executor of my mother's estate has been using her credit cards and has opened up new ones in her name. She has been deceased for over 5 years. what is he guilty of. The charges amount to far over 100.000.00. In reported it to the prosecutor's office. They told me to contact the credit card companies and close the accounts, ironically, I can't because I am not the executor of the estate. what happens next?

There are numerous criminal laws that could apply. What charge might actually be filed will depend upon those chosen by the prosecutor, if and when the matter is reported to the police.

I'm surprised that the credit cards and credit reports still work. Usually what happens is that the information is reported to the Death Master File, and the cards get closed and the credit reports flagged so that this very thing can't happen for long. Is he still getting her social security checks?