I had a dcg that I suspected of having selective mutism. I suggested several times for mom to take her to the doctors to enquire about it. She never did. whenever I approached the subject mom would agree that something was not right but mom never acted on it. I called our local Child Developmental Center and enquired about this. The worker then had a discussion with Mental Health. The worker suggested I pass along the phone number for Mental Health. I knew mom definitely wouldn't call there so I gave her the number for the Child Developmental Center. She never called.
This girl is now in kindergarten so she isn't in my care any longer. I talked to the mom about a month ago and asked if she's getting any help at school. She said since the girl is doing so well in all other areas, she isn't getting help.
I also wouldn't want to diagnose a child. I just told mom about my suspicions making it clear that I don't have the qualifications for a professional opinion. But it comes down to the fact that it's up to the parent as to whether they're going to pursue it or not.