You have not mentioned whether this is the first episode or he has history of same episodes earlier. Montek LC is an antiallergic and it contains monteleukast and levocetrizine. It is not indicated for such a long duration in first attack.
Get a eosinophil count
and serum IgE level done as that will help in diagnosis and also in assessment of response to therapy, if it is recurrent.
In case of allergic rhinitis
or mild persistent asthma
there is proven role of Montelukast
and cetrizine to control the disease process and in prevention of attack.