Is there family history of asthma? You have not mentioned about the investigations. Is he suffering form eosinophilia? Try to avoid exposure to dust and smoke as far as possible. If there are pet animals it is better to avoid contact with those. See whether the attacks are precipitated by any food. Avoid artificial flavors and preservatives as much as possible. Encourage him to do yogasanas. Reduce intake of dairy products. Long term use of steroids
can cause growth retardation. You may try BRESOL
syrup after thorough evaluation.