Tell your son that this has to be signed, the letter or form letting you see his records because otherwise there will be no $$ to pay for his new CD's, games, sports, books, whatever because all the $$ will have to pay the doctors. That the insurance is demanding it or they won't pay. And without the insurance paying, NO $$$ for ANYTHING fun. Name whatever he thinks is most vital to his life. Cable TV, movies, meals out. Meals with his favorite foods, whatever.
If this does not work, there is the line I have taken with my kids (we lived in a state where I learned that at age 12 he could keep me from even talking to his docs during his appts!!). I started when I learned of this with the line that as the parent it is my job to make the medical decisions. I have had the years and education to know what is going on. And if, by any reason, the child keeps me out of an appointment, or refuses access to medical records, the child's life as he/she knows it will be OVER in our house. I started very young with this, and was quite consistent. MEdical issues are one area where the kids know I WILL listen to them and their concerns, strongly weigh their requests for doctors, etc..., but I and only I make the final decision. husband does not know enough about most of what they go through to make any decisions, or want to. BUT they also know that husband and I are a UNIT and the "I" means mom and dad.
I just did a search on HIPAA, teens and medical records. Apparently family planning and STD records, as well as mental health records are limited on a state-by state basis, as well as by HIPAA and healthcare providers. Mindboggling, but true.
I would say that you try to access records through your insurance company. I can get all sorts of stuff on my son through our health insurance co. I do know that I insisted on adding a consent to treat and financial responsibility acceptance forms to my daughter's doctor when we took her in for gyn troubles this year. The doctor has a policy of treating the teens if they come in (and I know she eats a lot of this cost), but I made sure papaerwork would let her get treatment without me if she felt she needed it. I feel this is important because too many teens get into sexual situations with-o protection, information, or approp medical care if needed.
Good Luck,
Susie
ps. might try the insurance forum, maybe they would have an idea?