Does anybody know if this will hold up in court. In other words can this be used to bring a suit against the watchtower?
No it won't. The Watchtower is also free to associate or not associate with people as it sees fit. And you're free to leave if you want. Your family and freinds are free to stop talking to you if they so desire. The UN statement on freedom of religion is more like a goal or a statement of principle than a law.