I really can't add any more about
what she should do, to be honest. She has different health problems that need addressing and should have a doctor that does this without blowing her needs off as if they're not important. This sometimes happens to older people (and especially to older women, I might add), but these health concerns are important. Regulating blood sugar is tricky because there are other factors besides the food she eats that affect it: lifestyle, other meds, pain, being sickly, etc. That all needs to be taken into account
When you say she eats well, I don't exactly understand what you mean. Can you give me what she eats everyday? For different meals? And what she drinks?
I can't help you with supplements personally, sorry. Beside the link in my signature, you might check into the books and website for Richard Bernstein, M.D. He is a type 1 diabetic and has written a very detailed book The Diabetes Solution
. You might also check out his other website: http://www.diabetes-book.com/