This is a condition where fluid builds up on the brain. The cure is to put a shunt/drain in the brain and run it down to the kidneys.
Not to be picky, but the surgical assistant in me has to make a correction.
The shunt is known as a ventriculoperitoneal (V-P) shunt. A small tube is inserted in a ventricle of the brain then routed under the skin to the abdominal cavity (peritoneum), not the kidney, where the fluid drains and is absorbed.
While it certainly sounds scary, its not an uncommon procedure and is relatively minor as cranial surgeries go. I worked with a registered nurse who had a V-P shunt since she was very small. She had to have it replaced a couple times as she grew, but she is none the worse for it.
I hope all turns out well for your son.