Hi welcome to Health care magic forum. So your son is using the drugs monticope since 3months it is a good drug to fight allergy
and to prevent it. Nebuliser is used to relax the bronchial constriction, probably he must be having some silent broncho constriction.(breathing problem) if it is more he may need anti biotics and steroides. but bonticope try to controle the disease.
Besides i advise you some diet recomendations for him, as avoid giving cool drinks, cool water, ice cream, sweets, chacolates, sea foods, junk foods, oily foods till he gets some resistance.
Give him more of green leafy vegetables, pulses, sprouts, dry fruits to build resistance and blood. Wishing him fast recovery and thanks for calling.