What causes a horse voice &u lingering cough &u runny nose? what can i do for it with a 4yr old?

Could be diet: What you describe is a series of reflexes, all of which could be exaggerated by diet. This sounds strange but so many kids are allowed ad lib sweets and this kind of malnutrtion causes sensitivity in the reflex control mechanisms . This is particularly true if you note that he coughs in his sleep, and even more so if he has temper tantrums. These symptoms are usually regarded as infection.

Reflux/nodules/allrg: This pattern brings to mind cases where the child had mild reflux that increased with feeds before bedtime, producing night cough. Some made it onto the vocal cords causing nodules or swelling. Runny nose can be due to reflux irritation of the backside of the nasal passages. An ENT evaluation would help. Sometimes avoiding late feeds has helped.