Leo says Chromecast can be used as a compliment, but not a replacement for AppleTV. If he has a good internet connection, then Chromecast can give him 4K resolution. It's easy to control using an iPhone. And at $35, it's a great deal. It is a bit limited in what can support it at the moment, but more and more apps are coming online now.
Another option is the Roku, which just came out with a new version of it's streaming stick for $50. But the best quality on Netflix is usually Apple TV.