My 75 Year Old Friend Has Had Hep-c, She Has

My 75 year old friend has had Hep-c, she has lost one kidney. For 5 years she has been going to kidney dialysis. All of a sudden, she is refusing to go. On the mornings she is to go, she begins to vomit, and refuses to go. It has been several weeks since her last treatment. How long can she go without having dialysis? She refuses to see her physician also. I am very concerned.