Is My Friend S Persistent Fever And Mild Cough Related To His Dust Allergy, And Is Allegra-M Appropriate?

Dear Sir, my friend is allergic to dust and he usually get fever if inhale dust. he is having fever since last 1 month. temperature goes around 99.4 F. after taking paracetamol the temperature becomes normal and again he got fever after 20 hours. oxygen level SPO2 is between 97 to 99. he dont have any other symptom. sometime he do little cough in morning only. earlier he was taking allegra 180mg( fexofenadine hydrochloride). Now he is taking Allegra M(fexofenadine hydrochloride and montulakast). please suggest is this medicine ok. or is this the symptom of coronavirus.