From my experience it is really hard working with family. I have to keep remembering we are all a work in progress because it is a social disease. I imagine finding a WFBP counseler will be a challenge but maybe getting them to sit through a moive might help. I really liked this YouTube BBQ posted on QA of Eating You Alive
http://youtu.be/S22oMpjcwuEIn essence it states to show your concern of losing them as it our nature to want to help and they might make that turn to help you. And be the best example you can be. The biggest two fears is food won't be tasty enough and they won't be satisfied.
They didn't mention it but I think digestion is a issue/concern that isn't talked about. Having a issue of "Dr McDougall's Digestive Tune Up" and "McDougall's Medicine: A Challenging Second Opinion" around the house is good for reference. Most important keep working on yourself.
You can always go to a Ala-non meeting for support in fact I should give that a try. I think it is really true, in the above link it is our nature to want to help, and that message will resonate you want help. I have found members in Ala-non have very clever and loving approaches. And of course food/money is the core as taste/satity.
Aloha, Patty