The best way for her to lose pounds will be to cut on the amount of calories she takes in daily in her diet. She needs to eat less than 1,250 calories per day and force herself onto an elliptical machine for at least 10 minutes. She can also talk to the doctor about liquid diets. Medically supervised liquid diets consist of protein shakes drunk throughout the day. For more information, visit http://www.livestrong.com/article/40950-lose-pounds-fast/.
That is substantial amount of weight, besides exercising more often, eating healthy with smaller portions, cutting out high fat,sugar, high carb, fried foods she should be under doctor supervision for health reasons. Good luck!