If he’s paying the fee, the government is in the wrong and he can sue. If the government decided to stop allowing grazing, then he’s claiming “squatter’s rights” and the rancher is in the wrong.
He stopped paying the leasing fee many years ago but he kept running cows on it.
there is a 1980’s USSC that states you can not take without compensation.
I would want to know more about this court case. Cattle grazing has a whole different set of land rules. (it is like riparian rights)