PS--Even if nothing suggested on this site is helphul, don't give up hope--keep at it until you find good help. Vestibular (balance/vertigo/dizziness) problems are often difficult to find good treatment for. Doctors are humans who are just trying to collect a paycheck, and because dizziness is somewhat difficult to measure, they rely on patient descriptions of symptoms. If a patient describes a symptom the doctor isn't familiar with, it's easy for them to either pass it off as anxiety or tell the patient, "No, you must be experiencing X, not Y." If a doctor doesn't understand your symptoms, they will not be able to treat you properly. If a doctor isn't listening to your husband, find a new one. The world is big, and there is truly a large amount of medical knowledge out there, if you can find your way to it.

Second opinion services can be helpful. Sometimes an employer will offer one as a benefit. Both Cleveland Clinic and Johns Hopkins offer an online second opinion service, though I think those each cost around $500.