My doctor told me that type 2 diabetics who have bariatric surgery become non-diabetic. This is because the surgery causes them to lose enough weight to become normal weighted and their insulin resistance genereally decreases as their weight decreases. Their A1cs drop to non-diabetic levels too. This is true as long as their pancreas is not burned out. IN that case, they are unable to make enough insulin for their metabolic needs and they are reclassified as type 1, or 1.5 if their insulin resistance persists.
Maybe this is what your friend's doctor had in mind?
Some doctors tell you that once you cross the line into diabetes, you are always a diabetic no matter what. Maybe you enter a type of diabetes remission if you lose weight and change your lifestyle- but it's always there lurking in the background.
Based on the recent findings of multiple gene involvement in the development of diabetes, I'm tending toward believing the lurking in the background theory. If you have the genes, you have the genes. Diligence and adherence to a non-diabetes promoting lifestyle may help you to not cross the line. It's kind of like walking around with a loaded gun- you don't have to fire it.
good luck
sandy