Spirit Airlines Monopolizing Off CANCER patients! Plano Texas

My sister is a 24 year old single mother of a 5 year old girl.  She purchased tickets in advance to obey a court order to bring her daughter for spring break visitation to her father.  A few weeks ago,  she was diagnosed with cancer and immediately started chemo.  The oncologist said flying was not an option and that they would supply a letter to give the airline so they could change the name on her tickets so that one of us could go on her behalf.  It's a common thing that the airlines support in the situation.  NOT SPIRIT AIRLINES! They gave her the option to FORFEIT her money and tickets,  pay $500 more to change the tickets,  or risk her health and pay nothing more.  Because it's court ordered and she doesn't have extra money, she is having to fly and risk her health.  This is obsurd and should be illegal!!