How long can a person live with near kidney failure?

What is the life expectancy for someone whose heart and kidneys are on the "edge" of failure?

My MIL was diagnosed with hemochromatosis 25 years ago. Recently, she was hospitalized and diagnosed with congestive heart failure. Her kidneys also began to fail and she gained 16 pounds of water. Miraculously, her kidneys kicked back into gear and she lost all the water weight. She then got an infection in her leg and blood poisoning. Her kidneys began to fail and she was in ICU for five days. The hospital had the talk with us re: quantity of live vs. quality and we were prepared to bring her home and let hospice take-over her care. Suddenly today, she rallied and ate a full meal for the first time in at least two weeks. Given the severity of her condition, what is her life expectancy? Could she come back around?