The basement is a common place for mold to grow, here's what I found on this topic: Basements & Crawl spaces have the most potential of developing mold than any other area of the home because of their damp environments & moisture. Mold can develop frequently on wooden materials in the basement especially in the framing. This can lead to allergies & symptoms of mold which can also cause mold poisoning, you can find more on this subject here
http://www.blackmoldremovalsupport.com/mol
d-poisoning.html
The article says There are also less common symptoms that black mold causes including respiratory infections, seizure, heart attack, chronic fatigue, infertility, swollen lymph nodes, multiple sclerosis, depression, anxiety, stress & inability to deal with stress, weight gain, panic attacks, etc.
That should be enough to make your husband take black mold seriously!!