Mineral rights

My stepfather has 40 acres of mineral rights in Richland County. He passed away a couple years ago and never signed his rights over to my mother (over-site on their part).

A lawyer from MN and now AZ have been working on it but hit a lot of walls as to the steps to take to get the rights into her name.

Anyone gone through this or have any suggestions?

Thanks for any information.

Diane