i would guess that on the face of it as you have described it that your husband qualified because it could be dangerous to his health to work, whereas you could work (even if it was something different from what you are doing now) for example, i also have severe RA (and far too many appointments in my opinion!!) and couldnt carry on working as a nurse. in stead i got a desk job that i could do from a wheelchair.
From the incredibly limited info you have given, it seems this is what could have happened. IB does not reply on how often you see the docs nor how much medication you take, rather you ability to work