Please can i get some help? how long do people usually live if they have chronic kidney failure?

It depends: It depends upon may different factors. But, rather than trying to give a simple answer, go to this website (reputable organization) and read about Stage 4 renal disease: http://www.kidney.org/patients/peers/stage4.cfm. There is great info there.

Longevity and ESRD: Patients with ESRD live shorter lives than age-matched control without ESRD. Their longevity depends on their age when they start dialysis and what other co-morbidities they have, such as diabetes. For a more specific answer you need to supply that information. You can, or course, ask the nephrologist treating the patient you are asking about for a more meaningful answer to your question.