It is something I could see an attorney suggesting be done while in the care of the mother...setting up an appointment to see a child psychologist/therapist to use in a custody dispute. While all medical procedures can be performed with a release from the mother while he is in her care, Ronald being the legal custodian still has the right under the law to be privy to any and all information from such visits.
She is supposed to report it to Ronald, but this doesn't mean it will happen. Unless Rj tells him he went to see a "nice person where he played games", he may never know until he picks up the phone and calls every one in the area to confirm if a visit occurred.
He has a legal right to know and the doctor/therapist most likely won't call him.