this seems to be a viral infection and will most probably be self-limiting in 5 to 10 days. she needs to do gargles with lukewarm saline water (water with salt in it). i advise her to brush the teeth as usual twice a day especially before going to bed. ask her to take plenty of fluids and proper rest for better results. for fever i suggest acetaminophen every 4 hourly until there is no more fever. she can consult her doctor discuss with him or her and take the medicine with consent. for further doubts consult an internal medicine physician online --> <link>
kindly give your advise for my breastfeeding wife's cold and fever.