Here's the setup: It is a fantasy novel, with very little magic in it. MC is stabbed in the kidney in a busy marketplace, the assailant takes off and two of MC's companions follow while the third friend administers some sort of emergency care until a healer(magic using doctor type) can be located.

I want this particular event to stay as true to RL as possible, sure there is magic in this universe but it is used as a last resort sort of thing. I know there is a short amount of time between an injury to the kidney and death, or so I have been told.

I ask you folks; what can the friend do to assist? After treatment how long does it take for someone to recover from such an injury? If this were to happen here in our world what sort of treatment could a person expect after an injury like this? What restrictions would be placed on a patient recovering from a stabbing?