My 4 Month Old Haa Severe Cough In Chest Since

My 4 month old haa severe cough in chest since 2 days. My doctor have prescribed Alex-p syp 2.5ml thrice a day ,moxclav drops 10drops twice a day and betnesol oral drops 8drops trice a day(2times after two days) these all to be given for 5days. Please suggest me weather these all will work or should I change the doctor.