Life Expectancy for someone with Stage V Kidney disease?

Hello everyone, my grandfather has this condition. He's 76 years old and has been sick for a long time. Basically I think the initial problem was caused by decades of alcoholism and possible high blood pressure.

I talked with him on the phone the other night and he was extremely fatigue and sounded terrible. I know he doesn't have much longer to live, but I'd appreciate if its possible to estimate how much longer? He is getting treatment and dialysis and all that. If anyone can help out it'd be highly appreciated thanks.