Hello, this is Dr. David. I have read your question and I'm ready to help.
there is no way to stop your immune system.
the best way to help your pancreas and pancreatic cells is to loose weight and exercise and diet and cut calories.
and avoid alcohol
make sure you swing your arms and speed walk to get your heart rate up to 110-140 beats per minute to get an aerobic workup when you walk to help you loose weight.
see a dietician and nutritionist to maximize your dieting
by loosing weight, you will give your pancreas less work to do and prevent diabetes.
make sure you TSH levels or thyroid
stimulating hormone levels are between 0.3 and 3.0. if your TSH levels are above 3.0, you can be hypothyroid and this can make weight loss more difficult.
I have graves disease myself and destroyed my thyroid gland with I-131 dosing.
let me know if you have questions.