I think the therapist is doing the right thing. I would be livid if my parent could have spoken with my T at that age. Their trust is fragile at that age, and if you were allowed to talk with the T the child could shut down, feeling like they are being gained up on, instead of being 'teamed' with the T on their side.

If you want a say, talk to your child about possibly going into family therapy. It could be with the same, or a different T. But it sounds like her T thinks it's very important that they stay one-on-one with eachother and not invade that.