The only person who can legally cash a check for a deceased person is the executor/executrix of their estate according to the Law School at Cornell. If a will was not established authorizing such an agent, the heirs will need to go to probate court to be issued letters of testamentary.
The executor/executrix of an estate should take the check to an appropriate financial institute to deposit or cash it. The executor will need to endorse the back like so:
by (signature of executor/executrix)
Executor/Executrix of the Estate of PayeeAnyone who is not the executor/executrix must then go to probate court to be legally appointed as the executor/executrix. This can be time consuming, and all individuals must have the proper documents in order or risk the court denying the request. For those unsure of the process, there are probate attorneys who work with individuals in these situations.