Thanks for your query,based on the facts that you have posted it appears that your friend has Chronic Renal Paranchymal disease .It is progressive disease and one can not pull on life long on dialysis
and has to get renal transplant done .
Life span depends upon the creatinine
level and effect of renal disease
on other organs and systems of the body,
I would advise not to go for his marriage .
Renal transplant is the only option till then he has to undergo dialysis till he gets kidney