Ward County - South Lone Tree Field - Reaffirmation of 1964 Lease?

My family has received an offer from Enduro Operating, LLC to Reaffirm a Lease for Oil and Gas executed by my grandparents in 1964. It calls for 1/8 % royalties. Enduro is offering my mother $50 per acre for her portion (8.775 acres). I don't know what the other 5 beneficiaries have been offered as my family isn't on good speaking terms. Should she try to renogiate for better royalty payments in line with what is being offered today? Can she ask to limit the lease to 3 or 5 years? As it stands now it goes on forever as long as the well is producing. The location is Township 155 W R-85-W. Any help would be greatly appreciated.

I have recently inherited mineral intrest from a life estate and although I am still in process going through probate and have not had to deal with any offers of holding I have in N. Dakota I will say in my limited experience a 1/8th royalty is low. The lowest I have signed for negotiating leases in Oklahoma, Texas, and Colorado is 3/16th and I have even been able to get a 1/5th option with a signing bonus on some land. The first offer you get from a company is hardly ever there best offer. Hope this helps