Hi Julie,
Your husband should have a test called hemoglobin electrophoresis (a simple blood test). This should determine if he is indeed a beta thal carrier. If this is confirmed, his family should also be encouraged to be tested, because if they are carriers and have a child with another carrier, there is a 25% chance of the child being thal major, which is a lifelong chronic condition that requires blood transfusions and much care and treatment. Carriers are much better off knowing their status so they can make informed decisions.
In your bio you mention that the doctor said your husband is low iron. Doctors often make this statement based on a low hemoglobin or hematocrit level, but this does not actually mean the patient is iron deficient because there are other causes of anemia. If his Hb is low because of beta thal, iron will not help at all and should be avoided. A group of blood tests called iron studies can determine his actual iron status and whether he needs supplements.