Professional way to ask a parent for copy of custody papers, as a child psychologist

Interesting. That question to me seems governor and more by the ethical and professional rules of your profession, not the legal profession, but I can contribute. Just like for me to do a proper analysis of someone's legal situation, I need to see all the evidence that contributes to that situation, it would seem to analyze an adolescent who deals with issues from a divorce, whether directly or indirectly, you would have to see the evidence. I would think the key part would be making a clear and simple explanation to the parents of the therapeutic need. It seems they've taken the step to bring the child or adolescent to you, so they aren't therapy resistant, necessarily. Obviously material in your office is confidential just like in their lawyer's office. I think if you are confident and present your needs to them, the professionalism you show will put them at ease