MOST attorneys will give a free first consultation to discuss if there are merits for situations just as this. It gives them the chance to see if the ambulance is there and if it is worth chasing.
As far as the statement of make them fire her, don't give up. The difference is when she applies for another position, they will want to know; why she left? fired, why? resigned, why? Fired from last position may not set well with prospective employers. Again, not right, but reality.
A voluntary resignation might get her unemployment benefits denied. Depends on how quickly and easily she could replace her income at the same level.