Imagine all the thoughts that would run through your head if you were alone with a loved one who suddenly fell ill. You are the only one who can help, and if you don't do the correct thing, they might not make it. The pressure is on.
What do you do? The best thing you can do is to contact a medical professional. Calling 911 is the best thing you can do in an emergency, because the first thing the dispatcher will do is send you emergency personnel to care for the patient. Not only that, but he or she will also help walk through what you need to be doing until the rescuers arrive.
Imagine a four-year-old child being the caretaker calling 911 in this situation. Now imagine that the person the four-year-old is calling about is his mom - one of the two most important people in a child's life. That was the situation this child was in - and it managed to work out just fine.
This young boy did a stellar job - but even more impressive was the 911 operator on the other side. She kept the boy calm and walked him through it. She is a saint and hopefully this will inspire others to work at the same level she does.