As someone that experienced DKA when I was young I'm still not sure how that happens unless there were a lot of other confounding factors. Having hypoglycemia that high for a while will make everything start smelling like varnish. Also you start physically hurting especially your kidneys which is not something you can ignore.

If there were other confounding factors then I'm wondering what their endo told them, unless this is one of those countries you could buy it without a prescription? Any endo with any training would have a fragile diabetic using more than one monitoring method and have them doing regular blood tests.