My 7 year old son has asthma. When he gets a cold, his asthma flares up and his cough is horrible night. Is there anything I can do to help his cough or make him more comfortable, besides the normal medication. He does take singular everynight and uses his inhaler when needed. When he gets these cought attacks, he is up all night and his eyes and nose become very swollen.
You can try using a humidifier or vaporizer to help moisten the air. That may help somewhat. Aside from that, I'd double your efforts to eliminate all triggers from his bedroom. If dust mites are a problem, encase mattresses and pillows in allergen-proof covers. Wash bedding every week in hot water. Keep pets out of the bedroom.
If none of that helps, then it may be that your son's asthma is not under control and you will need to talk with his doctor about changing the treatment plan so that it is more effective.