I'm glad you came here. You and Paul have been given a lot of misinformation. Hydro has been treatable for about 100 years. In the past 50 or so, since the invention of the Holter shunt in '56, survival rate has steadily increased. To quote a site I just pulled up: "Untreated hydrocephalus has a survival rate of 4050%, with the survivors having varying degrees of intellectual, physical, and neurological disabilities. Prognosis for treated hydrocephalus varies, depending on the cause. If the child survives for one year, more than 80% will have a fairly normal lifespan. Approximately one-third will have normal intellectual function, but neurological difficulties may persist. Hydrocephalus not associated with infection has the best prognosis, and hydrocephalus caused by tumors has a very poor prognosis. About 50% of all children who receive appropriate treatment and follow up will develop IQs in the near-normal or normal range."
I suspect Paul had a type of infantile hydro that can resolve. The name escapes me at the moment, but there is such a type. About 1/3 to 1/2 eventually have surgery.
To treat hydro in infancy, which is the most common time, a silicone shunt (catheter) with a one-way valve is implanted into the ventricle, threaded down one side of the body, and drains into the peritoneal cavity where the fluid is absorbed into the bloodstream. Shunts last an average of about 10 years, but I know some people who have had dozens and dozens of surgeries and others, like me, who have had just a few. (I have had a total of six.)
Please keep asking any questions you have. We're here to help.