I am a bit confused.....
What do you mean "medical papers" stating she is not allowed to see him? Who would get papers and who would then not be able to see the boy?
In my opinion if she has tried THREE times to get a temp custody order overturned, and has not been successful, that is more than a paperwork screw up.
I think her only recourse is going to be to hire a lawyer. But I would try legal aide. She also needs to decide what she wants, and then determine if it's in the best interest of her son..... Does she want custody back? Visitation? Is she in a position (mentally, physically, emotionally) to re-engage with her son?
Depending on her situation.... she might want to focus her energy on getting her life together, first. Does she have a job? a stable place to live? How long has it been? How old is the child now?
Those are things that a judge would look at.
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ETA - if she is providing medical care, then she should be able to get the name of the counselor, it would be on an Explanation of Benefits (provided the counselor was paid for using insurance).
This is why she needs a lawyer. Grandma can't keep paperwork. The Grandma may be able to keep the paperwork from being seen by a girl, but the counselor should have to testify officially (or provide an official affidavit) if they feel it's in the best interest of the child to sever ties with mom.
Most lawyers will allow you to set up a payment plan. They will take a $500 retainer (for the first amount) and then you pay as you go. Or find someone who will take her case pro bono. University of Iowa has a law school (if that's where she is.... your profile said Iowa, so I guessed). Call and see if they know anyone who can take cases probono or if their family law professors take on cases. Sometimes they have to take on a certain # of cases to "keep active" and this would be a good way to get reduced rates.