I have heard this sort of story a million times, personally in my own life and from people that I care about. It breaks my heart. It takes one strong person to sound the alarm but then no one wants to believe, its somehow easier to believe that the mom is crazy and emotional than believe reality.
The therapist ordered by the court is always biased in some way and judges are rarely trained on child abuse. It is maddening.
It seems that these issues will continue to happen as long as your daughter has contact with that part of her family. If you decide to go to the courts again, check out Evidence Based Inc. They do a social worker meeting and add to it a forensic investigator, they interview everyone, they compile evidence like a real honest to goodness police investigation, and then take all the data and plug it into a piece of software they created that looks at patterns of abuse and can spit out how probable it is that abuse is occurring and who is doing it, its so accurate that cases rarely go to court after it spits out data and all of their cases have sided with their findings. Their web site isn't even up yet, I have been working with them and I feel like I found a way to actually help people going through this. Check out http://dev359.gscadmin.com/ A judge might argue with you, they wouldn't dare argue with retired police officers who specialize in forensic investigations surrounding child abuse. The person I would recommend is Karen Borders, she is a tiger and I know she has heard some "wild and crazy stories" that always end up being true. I have heard stories about her, she is one tough cookie when it comes to protecting children.