Does he have a smart phone? A tablet? Is there no wireless device in his entire house? No wireless radio or camera, or any other wireless device? If there isn't today, there will be soon.. And as long as one is buying a new router, why not get one that provides good high speed wireless coverage as well as gigabit wired? Of course the answer to that is obvious, which is why there are fewer and fewer wired-only routers being made and sold (many stores don't even sell wired-only routers any more).
And as I said, if you're satisfied with a 150mbps 2.4Ghz-only wireless router, or even worse, with horrific wireless G throughput, then go for it.
But I certainly wouldn't recommend it to anyone else.