Call her doctor, make an appointment, save it in her calendar, remind her in the lead up, drive her there, get the referral. Walk her to the post box to send it off, sit next to her to phone the intake office to confirm they got the referral, set appointments on her phone for every 6 months to sit with her and call to check the cancellation list until you get an appointment. Drive her to that appointment.

If she has ADHD, the steps involved in getting a diagnosis are bigger than Mt Everest, she will need a neurotypical Sherpa.