Yeah, emulation and piracy is really not part of the conversation of which device to buy. If he was looking to emulate, there would really be no point in buying a Wii U to begin with, now would there?
It does bear mentioning that the Wii U has a few other advantages over the Switch. One, it has more video streaming apps: Netflix, Amazon, Hulu, and Youtube can all be watched on the Wii U, while the Switch only has Hulu at the moment (the Wii U's Youtube app suffers from frame rate stuttering, though). Two, it has an easily accessible library of retro Nintendo games through the "Virtual Console" on the Nintendo eShop digital storefront. Virtually every Nintendo system, except Gamecube, is represented. Nintendo isn't going to put any retro games up for sale individually on Switch, but rather is going to include an assortment of games with their online subscription service for Switch. It hasn't launched yet, but when it launches it's just going to have a bunch of NES games. Eventually the Switch's retro games catalog may surpass the Wii U, but right now the Wii U is a far better choice if you want to play retro games.