The latest discoveries in diet are far beyond what we have known in the past. For your mom, getting her diabetes under excellent control is the first step. Learning about the "nano technology" recently discovered in food is KEY! Buy the book Super Foods RX. Learn the material. Become expert on what healthy nutrition is and you will be able to rehabilitate your mom into a person running on "race gas"! She will feel great, she will be fighting disease. You never know, she may get her diabetes under control so well that she may be able to care for herself with diet alone and be free from any meds or insulin!
Walking is also KEY! She should start wherever she is, even if that is to the mailbox out on the property or something, working up to 30 minutes a day.
Walking will not only have great physical results, but it helps in the secretion of endorphins or "happy juice" that makes people feel great. She will begin building muscle and her metabolism will increase. Walking is also FREE!
Best of luck to your mom and remember, A Journey Begins with a Single Step!