I'm sorry to hear about your mother.

It's very sad when diabetics can't manage effective dietary changes. It doesn't help that there is so little societal support for diabetics not eating sugar, white flour and tons of other carbs.

What I'm wondering is if a robust prebiotic/probiotic intervention or other measures to improve gut health would enable people to take Metformin.

When I was diagnosed the endocrinologist prescribed Metformin, a sulfonylurea and diabetic teaching. I only took the Metformin and got a new doctor who supported a low carb diet.