You need to get rid of this ASAP!! Mold in air conditioning can cause Legionaries Disease!
Definition
By Mayo Clinic staff
First identified in 1976 as the result of an outbreak of pneumonia at an American Legion convention, Legionnaires' disease is a severe form of pneumonia. Legionnaires' disease is caused by a bacterium known as legionella.
You can't catch Legionnaires' disease from person-to-person contact. Instead, most people get Legionnaires' disease from inhaling the bacteria. Older adults, smokers and people with weakened immune systems are particularly susceptible to Legionnaires' disease.
Legionella bacterium also causes Pontiac fever, a milder illness resembling the flu. Separately or together, the two illnesses are sometimes called legionellosis. Pontiac fever usually clears on its own. But untreated Legionnaires' disease can be fatal. Although prompt treatment with antibiotics usually cures Legionnaires' disease, some people continue to experience problems after treatment.
I learned about this in college...it was caused by mold in the AC unit. Get help for you son right away! Good luck!