Great that someone is taking an interest in this boy and his CAH.  He needs to be educated.  At his age, even though he is legally still a child, he should be well equipped to handle his condition on his own.  After all, in another year or two, he may be out of the house.

You may need to get the father’s permission to go to the dr with the young man.  As a minor, I don’t believe he can authorize you to talk to the dr.  I don’t know about the privacy laws in your state, but you should check into that to see if you even can talk to the dr.  Meanwhile, this site has lots of good info, as well at the CARES Foundation site and MAGIC.  The Dept of Health in Texas also puts out some good CAH info.

Good luck in your efforts to educate this young man about his own health issues - and thanks for caring enough to do so.