if this is bronchitis, the problem is that there may be some swelling inside her lungs’ airways. It causes coughing, mucus and sometimes fever too. Give her lots of water to drink and let her have enough bed rest. Additionally, consider buying an OTC cough syrup with dextromethorphan for her. This will relieve the irritation in the throat making the cough less frequent and more productive. Do not exceed the recommended dose on the label without consulting a doctor or pharmacist first.