What Can Be Done For Child S Recurring Breathing Issues Despite Regular Inhaler And Medication Use?

My 5.5 years son sufferring from recurring breathing trouble with cold and cough from the age of two. Hw is regularly taking Inhaler Budecorte 100mg, and Asthhalin when breathing trouble is severe. Hw is also taking montAir 5 mg regullerly for last two years. But no beneficial effect till now. Please suggest.