Sounds like he may have Vertigo. I have a mild case of that, on top of my pretty severe motion sickness.
Over the past 4 years, I've eliminated Everest and Space Mountain from my line-up. I rode Star Tours once as a teen, and will never again.
I can ride Soarin, but there are a few times where I just have to look off to the side of the theater or up at the ride mechanical system, to affix my focus on something other than the screen.
There are many rides at Universal that I'll never do again, and they pretty much all have screens. My wife and I rode Forbidden Journey a few years ago. About 10 feet into the ride, I knew it was a mistake. I clamped my eyes shut, clenched the handles, and sweated profusely while praying for it to be over. I opened my eyes once when it slowed down, only to find our vehicle "floating" through a room that was entirely screens.
It's a bummer to not be able to enjoy those attractions, but I'd rather feel good the rest of the day.