Chronic lymphocytic leukemia life expectancy?

My grandfather urning eighty next year and only have one liver which is slowly failing. He has great memory ... and even continues to work (he's a doctor). He is very full of life and you can't even tell that he is sick. However, I want to know what the life expectancy usually is for CLL ... I can't find it anywhere. What is the most he'll probably live to? :(