I'm a type 1 diabetic and I have done the Clark Liver cleanse twice. I have not cured my diabetes yet, but feel this is an important aspect of curing type 1 diabetes.
In several forms of medicine including Ayurvedic and Tibetan medicine, diabetes is believed to be caused by bile backflowing through the pancreas when the hepatic duct is blocked. The bile is believed to cause the damage to the pancreas cells. As a type 1 diabetic for 20 years, I can remember having certain types of abdominal discomfort in the umbilical region prior to my diabetes diagnosis. While doing my first liver cleanse I could feel this same pain/discomfort in the same region and I passed 250 plus stones on the first try. The size of the stones was surprising.
Bottom line. It can't hurt, and can help greatly. Make sure your friend has cleaned her bowels before trying it.