You must get an ENT consultation done and get her throat examined by getting done flexible fiber optic naso pharyngo laryngoscopy
Without examination it is difficult to say the condition of throat and the food which she can take.
Also you can do--
Ask her to take liquids
Give her multivitamins
Liq. Xylocain gargle to make her mouth and throat numb for some time give it half an hour before meals .Betadine
Take care of reflux or acidity