Dear Sarah,thanks for query.Your sentiments are fine and understandable but you also need to know whether he will sustain this kind of major surgery.He is quite aged and major surgery at his age carries more risk,apart from he must be having other medical conditions like hypertension and diabetes which has lead to this kidney failure.Dialysis is of course a not a cure for this but this will help him to stay alive.please discuss this with your doctor also.Bye and take care.

Hi Sarah, Welcome to HealthcareMagic Forum.
I can understand your Problem, which is stressful both to the family and the Patient. If you are ready to donate him your Kidney you will be needed to get yourself examined by a Nephrologist to see if you are the right Donor to your Grandfather. He will run few blood tests and examinations on you and come to a conclusion. The survival rate after Kidney transplant varies from person to person and it is less if the patient is too old. Even if you become the right donor, the Doctors will consider if he really needs a transplant considering his age. Kindly discuss it with your Doctors as there are many risks involved in it.
I wish your Grandfather Good Health and Good Luck to you.