Hi Karen.
You need to understand the implications of food sensitivity, beyond the conventional medical understanding.
Lactaid is only as good as helping in digesting lactose which is the sugar in dairy, since your husband likely lacks lactase, the enzyme which breaks down lactose.
The key factors which should also be ruled out are casein, and cross-reactivity to dairy and other foods-reacting to it the same as to gluten.
Cyrex Labs website has detailed info on cross-reactivity. Look into:
Array #4 Gluten-Associated Cross-Reactive Foods and Foods Sensitivity.
A test your husband could also consider is Dr. Coca's Pulse Test, it's a free download, and it will indicate within a week,any reactivity, any allergies, any intolerance and sensitivity to anything ingested,
that is considered offensive by the immune system.
It is a great self-test, for the degree of accuracy.
Please note that this will never be a conventional medical test, since it is a self-test and therefore cannot be money/profit driven ( a prerequisite for "approved" tests and procedures)
There's another complete approach, which will likely work for him is the SCD program ,but requires strict adherence to some serious diet changes.
Best wishes,
Niko.