As a transplant patient, I am aware of the five stages of kidney [renal] failure. Stage 3 is considered "moderate" so there is time to correct her issues. Is "her doc" at a kidney transplant center, a Nephrologist, a doctor who specializes in treating kidney diseases? If not, she needs to see one. Google search these words - kidney transplant centers in xxxx. Where xxxx is the city your aunt resides in. You may have to use state instead of city if she lives in small town. TP Centers are where medical experts teach and practice.
She needs to formerly ask "her doc" to be referred to the center selected. In the meantime she can inquire at the center their processes for accepting referrals and papers she needs to fill out for insurance purposes. Then she needs to check with her insurance company if the center is listed with them as acceptable and what kidney disease treatments are covered.
Hello, I am not so familiar with the treatment for kidney disease, but know if it is bad enough it will involve dialysis probably for the rest of her life. Kidney transplant may or may not be an option, but is very complicated and expensive and would also depend on her overall health.
The most important thing for your aunt right now is to get her blood sugars under as tight control (with insulin, diet, exercise as much as she can tolerate and under medical supervision) as possible to hopefully help delay the progression and improve her prognosis.
Please encourage her to get a second opinion as well if she / you are not happy with her management.