My Son Is 60 Years Old And Recently Had A

My son is 60 years old and recently had a long bout of Bronchitis. Now weeks later, he is still coughing and is still very fatigued. Many tests have been done and he says he has a low iron count and very low hemoglobin results (not sure exacty what he said about these). His primary care doctor has referred him to an Infectious Disease doctor who has ordered a lot more tests.
So far his lungs look o.k. but I am worried about other possibilities. What does it sound like?