The person with power to handle an estate is called an executor (if there is a will), administrator (if no will or if the person appointed by the court is not named in the will), or personal representative (whether or not there is a will).
A person qualified to act as personal representative must be eighteen years old, never convicted of a felony (although there may be some exceptions), and if not appointed by a will, must also be a Nevada resident.
If a named executor has passed away or does not want to serve, the court will look to Nevada law to appoint someone else in order of priority. This includes the surviving spouse, children, parents, siblings, grandchildren, any family member entitled to a distribution from the estate, the public administrator, creditors, family members not entitled to distributions from the estate, and finally any person who is qualified.