For a lot of people, surgery only helps for a while.
I first had CTS when I was working at a pizza place and rolling dough by hand every day.
Then when I did janitorial work, mopping floors was really bad on my wrists.
Surprisingly, now that I spend most of my day typing code, it has pretty much gone away. The key for typing is to keep your keyboard in the right position so your wrists are neutral, not bent up or down.
I still get occasional flare-ups. Usually triggered by things like mowing the grass or doing things around the yard like shoveling or raking that require a tight grip. When it does flare up, the most helpful thing for me is wearing a wrist brace at night while I'm sleeping.
I would really recommend he wait until all other options are exhausted before doing the surgery. When I first got CTS and was doing research, it sounded like there were a LOT of people who were worse a few months after surgery.