I didn't say "Call an Ambulance". I said, "Call for Help". And, you don't know what kind of injuries are sustained until you have done an assessment. Most injuries are received at 0 elevation meaning a fall to the ground without any additional height involved, basically, Trip and Falls.
If you move someone who has an internal injury or a broken bone, you can cause further damage. It is best practice to allow the patient to move on their own if they can. That mother did just fine. She doesn't need The Reddit Brigade second guessing her.
But, never mind that I have spent 20 years involved in Mine Rescue and went through the process as my X became an EMT II and that I, myself, actually have 5 successful patient contacts. Please, Galt, continue with your completely WRONG arm chair quarterbacking. You'll make some lawyers a good paycheck someday.