What an awful situation for everybody involved; this is the essence of the "no-win" script. Unless something is done to change things, the pattern seems to be one in which each of the protagonists ("patients" or "clients") has a team of defenders and everybody is forced to take sides. This sounds like one of these cases in which anybody who gets "well" in individual therapy does so at the expense of the other family members. It is a perfect example of the complex cases that the family therapy movement emerged to handle. My personal recommendation would be that you try to make some connection with the therapists handling the other family members in order to get their cooperation in setting up a conference that includes all the players. These usually turn out to be fabulously effective in changing such puzzles.