Diet and exercise are the key.

First, you have to find out which type your mom has. Type I or type II. Type I patients can not produce insulin at all. Type II is not sensitive to insulin, but the patients still can produce insulin.

Diet and exercise are the fundamental measurements to keep diabetes under control. Eat small portion every 2 hours will prevent to have glucose peak. And regular exercise will increase the cellular sensitivity to insulin.

Hope it helps!