Here are a few items you may want to take a look at:
Pycnogenol is widely prescribed in Europe for diabetics. It helps lower blood glucose levels and helps protect against many of the conditions diabetics often suffer from, especially vision and nerve problems.
GTF chromium is considered by many to be the best form of chromium. GTF stands for "glucose tolerance factor". It helps the body properly transport and process glucose.
Another item to consider is magnesium. Most of us are deficient in magnesium and magnesium deficiency has been strongly linked to diabetes. Magnesium is also a good immune modulator, as is curcumin.
Have you tried blackseed oil (Nigella sativa). It has been used with very good success to treat diabetes and it too is a good immune modulator..
Needless to say "eating what she wants" is not a good plan, as diet and exercise remain the top tools for controlling diabetes.