Hello, Your husband has the history of being a chronic smoker, smokers tend to produce cough. The cough helps the body to clear out chemicals that enter the lungs and airways due to tobacco use. To avoid the phlegm from forming he should drink plenty of water. Lozenges and cough drops may soothe the throat. Steam therapy, exercises and quitting smoking will be helpful. However, you are suggested to get your husband clinically assessed by a GP. Get swab, sputum tests done. Get all Imaging tests (X-Ray, CT, MRI) done to rule out bronchitis, COPD, emphysema, lung cancer, etc. If reports are positive, get him treated at the earliest. Give him home made food. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician