My role is also that of client advocate. They have been bullied for too long and need a knowledgeable partner during this process. These are billable hours - I'm not donating my time. If I ran away, the client would be stuck in the same position they have been for too long.
Also, while I appreciate that you just want to get on with the job of creating the new site, I'd be weary about getting too involved with what is essentially a contract dispute between your client and a previous contractor.