We are in Denver, CO. and our son Ian had the spinal fusion surgery last summer, when he was 16. He came through it very well.
My advice would be to ask a lot of questions. I felt a lot better after learning more about the anesthesia he would be given and how it would be monitored. We also were able to talk to the anesthesiologist a couple of times. It gave us peace of mind to know that this person would take care of Ian.
Try to get some rest yourself before the surgery, because as a cargiver, your job will be somewhat increased. It's really important to take care of yourselves too.
He'll be in ICU after surgery, that is normal. They usually just feel more comfortable monitoring them more closely.
Try to take breaks during your stay at the hospital. I found that to be hard, but turned out to be a good thing in the end. We had some other family members sit with him while we were able to get some rest.
Let us know if you need anything else.
The Horan Family