That is so sad. :(
As people have already pointed out though, it wasn't an indication that it's "common." Simply that it has happened to her son and a few others.
I think, if I had a child with diabetes, I would lessen my fear of this by easing them into controlling their own diabetes. Let them take an active role early on, be constant support once they're doing it on their own, and continue supervising to make sure there are no unnecessary problems. Plus, continuous glucose monitoring!!! I think this should be considered standard diabetic care for anyone who chooses it. I got to do a trial week with a Dexcom last week. It warned me when my BG started dropping fast while behind the wheel of my car, and I felt safe going to sleep after an evening of struggling to keep my blood sugar up because I had it set to buzz if I hit a BG of 80. Invaluable! If I had a child and the CGM worked for him/her, I would feel about a million times better if they wore one.