How Can Severe Coughing Episodes Due To Bronchitis In A Child Be Treated And Cured?

Hello doctor, my son has severe bronchitis problem. He coughs too much. Doctor has prescribed salbair 4 times a days( 2 puffs each time) and budecort twice a day( 2 puffs each). And honetus syrup thrice a day, montine D syrup twice a day, nasal drops. He is still coughing a lot. He is 4 years old and his weight is 18 kgs.