I think if you were to ask most JW's whether they expect a miracle cure because of their faith, you will find they do not. I know I do not. What you will find instead is that they believe the promises Christ made of a resurrection. So, even even if the worst were to happen and we die while holding onto our integrity, Jehovah can, and will correct this.
It really gets down to a simple question: is God real to you or is this all just make believe? If he is real, and you trust him, you will follow his directions no matter what the short term outcome may be.
I had a heart attack about a year and a half ago. One in my family was horrified when she saw the words "NO BLOOD" written in large letters over my chart. I reasoned with her that if I were in a position that only a blood transfusion would save my life, would that be a good time to anger the only one could return me to life when the time came? She didn't get it -- God just isn't real enough to her. Too bad. I wish she could have the comfort a strong faith gives.