hello concerned parent ,first of all,let me reassure you most children who are in their active playing age presents in our clinic with similar symptoms. cold,cough and runny nose usually are basically due allergies ,common cold/flu like diseases or sinus infections.it has been often seen with some of my patients of the age group,that drinking milk or dairy products towards evening or at night seems to be a culprit. you can try basically give him a proper diet,keep him hydrated,avoid allergy causing substances as far as possible,try skipping diary products late evening or night. watch out for symptoms like recurrent throat/ear infection,fever ,strange sounding coughs,etc and in such case,then you see a pediatrician immediately. in normal cases,nasal deccongestants,antihistamines,humidified air,allergen free environment would alleviate symptoms. dont worry its normal for kids this age to have 7 to 10 episodes per year of similar nature . Hope that alleviates your concern and found this answer useful