I was born with an arachnoid cyst on my brain, they didn't find it until I was nine. I'm 29 now and I've had 99 shunt revisions since they first placed it. Despite how that my sound, I've been blessed being able to live a full life. I've worked full time since I was 13, played sports, I didn't even have trouble skydiving despite the Dr. telling me otherwise. Limitations vary from person to person, but I've known kids who have had just a few shunts placed, and they've lasted them their whole life. And they were able to live without the daily pain and discomfort.

They have made dramatic improvements on shunts in the last decade, which has given such better chances at a full life to kids/people. If your son has a medos valve/ programmable valve you have to be careful of magnets, because that's how the pressure changed on certain shunts without surgery.

FYI: There is a support group which is called S.T.A.R.S. that raises money for shunt research. It was started years ago in Detroit, they have event's and what not but more importantly other mothers & fathers who know exactly what your going thru.
I hope everything works out for you & I wish you and your son the best.
-Jesse