Hello. Your grandfather is suffering from acute on chronic kidney disease it seems, although further investigations are needed to ascertain the cause. Any operation at this point will be highly risky, as it may increase his kidney problem. He may even require dialysis support in post-operative period. A constant monitoring of kidney function will be required during and after the operation. My suggestion will be to.contact a Nephrologist immediately. Also discuss the issues in details with your Surgeon and Anesthesist. Hope this helps.