If she is carrying any excess weight, losing some of it might just be what she needs to keep her numbers down. She doesn't have to be thin, just a few pounds lighter will sometimes get the body to jump-start itself to better control.

Once you're a diabetic, even if in great control, any illnesses or emotional hardships might bring your numbers up and then medical interference will be needed. Then it's really p to the person themselves as to which way they want to handle it. There should be no shame in taking medication or insulin.