I can't believe what your brother is going through in trying to get diagnosed!!  In the large, major city we used to live in, I called all over looking for an endo who was familiar with CAH, and only found 1 who knew CAH well enough, but he only treated adults.  Have you tried searching your brother's area for an endo who is really experienced with CAH and has a lot of CAH patients, and then if the PCP won't send him to that endo, or that endo is out of the insurance network, can he call insurance and have them "ok" the matter.  After my daughter Erica died from an adrenal crisis, seems I have no problems "overriding" some things that I just won't put up with regarding insurance and general doctors.  So sad that they listen to me because of her death, and let me have my way when I tell them that I refuse to have another child die and "this" should be done.  What the heck is it going to take to get a good endo and the proper tests done on your brother?   Would DNA testing be of any benefit, showing he is a carrier or that he has CAH?