J.R.
Hi J.,
I have worked in the preschool/kindergarten school age for going on 3 years. In my experience when you have a parent who is in total denial there isn't much you can do for them.
But I am going to tell you, once that little girl gets into the school system, and enters kindergarten and she isn't any where near her other peers when it comes to socializing and learning, the teachers will step in. They will call for parent/teacher meetings, arrange for her to talk to doctors, social workers, etc.
So, just be there for her. In the end whatever the diagnosis maybe, shes going to need a friend.