Does my father automatically becomes the executor of an estate that my mother was an executor over now that she has died?

While the laws in each state are different, a Will should set forth successor Executors in the event the person named predeceases, resigns while acting or dies while acting. In the event that the Will does not name a successor, the residuary beneficiaries generally have the right to be named. It is more likely that you (and your siblings if any) have a priority right over that of your father. You should look at your grandmother's Will and check with the Probate Court clerk. This is probably an easy question for them to answer. I am sorry for your loss.

This response is for educational purposes only. It is not and is not intended to be legal advice for which you should seek the services of an attorney licensed in your state. This response does not create an attorney client relationship.

Not automatically. If your father was named as successor executor in the will, he should petition the probate court for letters testamentary. If your father was not named as executor, he can file a petition with the court to be appointed "administrator with the will annexed".