A stiff elbow can be caused by several things and developing one after an elbow injury isn’t unusual. The injury could have set off a chain of events that resulted in inflammation or perhaps there now are bits of bone or tissue in the joint that can cause pain.
Not all elbow stiffness requires surgery, especially if there is a fairly good range of motion, even if it’s not complete. However, surgery may be done to prevent the elbow from getting stiffer or causing more problems.
The best thing is for you nephew to speak with this doctor to find out why the surgery is needed, what could happen if he doesn’t have the surgery, and what exactly the surgeon plans on doing.