SandraHi Gg,
My 1st CAH son had an ACTH stim test done at 3 weeks of age. My now 3 month old son had one at two weeks of age. Your little guy being Hispanic has nothing to do with him having or not having an ACTH stim test. He is also not too young. Have you considered seeing another endo? It sounds like you have had many problems with him taking you seriously about getting to the bottom of what is going on with your little guy. If it were my son, I would look for another endo.
Sandra