Quite frankly, there's nothing to "do," exactly. (I wrote about this recently on the birth/first parent blog:
here.) This is a prime example of why being explicit in your desires for parenting PRIOR to the signing of TPR (or even prior to a match) can be so vital for expectant parents. Of course, as expectant parents, we don't always know the questions to ask. Quite frankly, the waiting families don't know, for sure, how they will parent either.
And so, while there's nothing you can DO, you just need to take care of you and the relationship. If it's getting in the way of how you are able to communicate with them or how you live your life, I encourage you to seek out counseling. As I said in the post, if your relationship is BEYOND strong, you can ask them in a non-confrontational manner why they've chosen acting for their child but whatever their answer is, you must simply, point-blank, accept. No questions. No arguments.
It's hard to watch your child be parented in a way that vastly differs from how you would want them to be parented. This is a tough pill for birth parents to swallow.