When is it time to see a Dr for a persistent cough?

My husband caught a virus on our honeymoon cruise September 10th. We have gone to 2 walk-in clinics since. The 1st one was in Boston....because the cruise had ended and we still had the journey back to rural NY. That MD prescribed Tesilon Perls 100 mg three times a day for 5 days. He said Jim's lungs sounded clear. No need for a chest x-ray (CXR).

Sept 26 was the 2nd visit to a walk in clinic.....here in my hometown area. His MDs are all in California!!! This Doc agreed his lungs sound clear....(no need for a CXR), diagnosed bronchitis......and ordered an albuterol inhaler and Zyrtec at bedtime. My concern is more about his MG since he is really not recovering the strength he had before all this began.