They basically just base it on questions, ie fever, systems, and days since diagnosis and last symptoms, if you use one of the telehealth places, like MD Anywhere. I have noticed that my husband and son seem to be coughing more too, since getting covid in June and July, respectively. We do have a lot of allergy stuff happening here right now that's affecting me, but I don't seem to have a cough. They are usually not affected as much by allergies as I am, but I also take/do more for mine on a daily basis. I wonder if the body can be more sensitive for a while after getting covid. If you are concerned, he probably should visit a doctor.