Recurrent dry cough. What should he do?

Hi My friend is suffering from dry cough sore throat and blood streaked sputum in morning. He gets this thing in a specific order. First severe sneezing and cold symptoms for 2-3 days followed by severe sore throat and after 2-3 days dry cough starts. He feels mild congestion in right lung with occassional mild pain. after 2-3 days of onset of dry cough blood streaked sputum starts in morning. whole day he is fine. After 8-9 days the cough resolves and blood streaked sputum also goes. but the same thing is recurring after 3-4 months and in last one year he has such 3 episodes. 2 years back he had similar symptoms, CT Chest Xray, AFB, Bronchoscopy all was clear. suggest what should he do?