My Sister Is Diabetic. Over The Last Couple Of Months

My sister is diabetic. Over the last couple of months she has had tingling & numbness
in her fingers and has lost underage of her had & arm. The doctors don't seem to be in a hurry to see what is goo g on. I want to get her to a good neurologist that will do something quickly. One doctor said she could loose her arm if something is not done quick but they just keep sending her to another doctor. She is scared.