Where do you live? Can you find another Ped. Endo?And NO, definitely DO NOT SHUT UP!!! You are your kid's advocate and care more than anyone else what happens to her...be persistent, even if he hates it. If he realizes that you know too much, maybe he'll get motivated to do a little research! But I think it's most important to follow your intuition as a parent.
Purchase the CAH book by Rivkees and Hsu - I think it's available on Amazon. The book has a wealth of information, and you could use it to point out common CAH dosing practices (among other things) to your endo. Maybe buy an extra copy for him!
When he's being snippy with you, ask him how many CAH children he's treated in the past. How many does he treat now? Is he up on all of the current research/dosing info/etc?
How did your daughter get her diagnosis?
I have a 20 month old daughter who was diagnosed at birth - if you'd like to talk offboard, you're welcome to e-mail me at alaskarocks at gmail.com.
Good luck with everything!