Hello, The medicines that your paediatrician has prescribed will help to relieve the symptoms your son is having and you should continue them in the dose and duration that your doctor has instructed. He will be relieved in a day or two.If he is having difficulty in breathing you can get him nebulized with duolin. You can also use saline nasal drops to relieve nasal congestion. Prop up his head while he sleeps as it will help him to breathe better.To boost his immunity make sure to give him a nutritious balanced diet and include a lot of fruits and nuts in his diet. You can also give him multivitamin syrup like zincovit for a few weeks. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr Nazma.amman, General & Family Physician