Suggest Medication For Bad Cough & Loss Of Appetite

hi please can you help? My 7 year old son has had a bad cough for 4 or 5 weeks now. The doctor intially prescribed a blue inhaler a few weeks ago and after another appt today prescribed the brown Preventer inhaler and nothing else. My son is off his food, totally wiped out and coughing very badly indeed, hardly sleeping either. I am at a loss what to do and a bit worried about the doctors very blase attitude to this. Any suggestions?so