l know someone that has total renal failure.Why would they need an insulin pump for this?

''Lower blood glucose levels mean lower risk of developing complications i.e. retinopathy, neuropathy, renal failure, cardiovascular disease . . . . ''
Thats why the insulin pump is needed.

That means someone is kidneys have totally shutdown! They will need dialasis, for at least 4hrs. a day, till they get things back to close to normal again. If your kidneys are not working, you probably wo not last long, without dialasis.

The person you are referring to likely had diabetes which is the number one cause of renal failure. The renal failure did not cause the diabetes, it is the other way around.

Insulin has to do with the diabetes. l am assuming they are diabetic. The renal failure is a side effect of the diabetes. Has nothing to do with insulin. Has everything to do with having too much poison or sugar running through the kidneys and they can not handle it. It is a consequence of uncontrolled diabetes. Means that your friend may have to be on a machine to clean their blood and they will also still not be making enough insulin which is from their pancreas.