This seems a very strange policy. It seems very unwise to terminate all family members based on the actions of only some of its members, for a start. And that's just bizarre that every member of the family wasn't given a warning letter to alert you that your therapy was at risk.

I would not want to work with an agency like this at all - they seem weirdly punitive and controlling. But I can understand the tough spot you are in- I would definitely appeal to your therapist and also have your husband talk to his about the ways the organization failed in its implementation of this policy, and the overall unfairness of it.