How Can Persistent Dry Cough In A Toddler Be Effectively Treated, Especially In Cold Weather?

Hi Doctor, My son is 2year 4month old . Last 3month he is coughing before sleeping and after sleeping in the morning. Doctor adviced to give levolin 2puff for 5days and budecort 2puff for 3weeks. Cough is dry not a wet cough. I m worried cough is been controlled not completely going away. And recently we moved to Bangalore which is cold weather. We have started giving amla juice to boost immunity..which is advised by doctor. No wheezing only dry cough . He consumes more biscuit (good day ,50 50) .