Suggest Treatment For Recurring Cold And Cough In A Child

Hi doctor, My son is 6 years and 4 months old. He frequently gets cold cough and cough increases very fast for him. I normally give him Priton-CS for dry cough or Cofstop for wet cough and Montair LC Kid syrup as well. But this reduces the cough for few days and again he gets the same. Please advice the proper treatment which is required.