If there was a Will, the executor should have filed it in the probate court in the county in which grandma lived. If the executor did not, then the next of kin can go to probate court and demand that it be filed, or seek to become administrator / personal representative and handle the estate as though she died without a will. As notice is given to lots of people, including all heirs at law, if there is a will the person then runs into court with it 99% of the time. Your grandmother's children are next of kin if alive, and if yorr parent is dead, then you are able to act.
This is intended as general information only, NOT legal advice. You are not my client and I have no obligation of any kind to you. To retain a lawyer I suggest you go to www.AttorneyPages.com.