Isn’t it great that at least you are taking an interest!  It sounds like he may have non-saltlosing CAH which oftens means less hospital treatment and less likelihood of an adrenal crisis.  One suggestion may be to ask if you can visit his doctor with him and work this out together, the doctor can explain everything to both of you.  However, as his father is on the scene, he may object to you taking such an interest in his son and his son’s medical condition, although if he is not that interested then he may be glad that someone else is!  Worth a try I guess.  At the very least it would be worth your daughter’s boyfriend visiting this site and others to find out as much information as he can for himself.  Good on you for caring.