The health insurer can put limitations on what it will pay for in order to save money or reduce costs: e.g. that generics will be used instead of name brands. That is legal. Remember: generics are approved for the use by the FDA and should have minimal (if any) differences with name brands. They can be prescribed for the same exact things. Since the FDA regards them as equivalent, the insurer can say it will only pay for the less expensive one: that is not interfering with the medical care, because the generic may be used for the same treatment and conditions. Further, the insurer could not force your husband to use the generic against his will: he had the right to get the name brand and pay out of pocket for it. All they did was say that IF you want the insurer to pay, it must be the generic version; that is legal.