Two problems. 1st, North Carolina an at-will employment state, (You can be fired at any time, for any reason). The only time an employment contract in NC is NOT at-will is if the employeer makes a specific contract to limit his reasons for fireing the employee.
Secondly, Employees of the Sheriff in NC can be fired at any time for any reason because they serve at his pleasure. He doesn't need a reason to fire the woman. He basically can say, "Hey, you've done a good job for me, but it's time for you to go. Goodbye".
The woman doesn't have a case, she can't force the sheriff to let her work for him.
Well, as long as there's no violation of the 14th Amendment, you may be right.
Secondly, Employees of the Sheriff in NC can be fired at any time for any reason because they serve at his pleasure. He doesn't need a reason to fire the woman. He basically can say, "Hey, you've done a good job for me, but it's time for you to go. Goodbye".
Can he fire all women if he chooses? How about all Hispanics? All Catholics? I would suspect there are limits even in North Carolina.