My son lives in an apartment complex that houses mostly college students. Since he moved in, he has been sick almost constantly with lung issues up to and including coughing up blood. We recently found that the air conditioning and heating unit in his apartment is covered in mold and mildew on the inside. Although they have come out and cleaned the unit, I think they need to do more than just cleaning the coils. Is that enough to get rid of the mold or are they just shoveling sand against the tide if they don't treat the ductwork as well as the rest of the apartment?