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My recommendation is Naoki Urasawa's Monster. It's 74 episodes long, so it may be quite the commitment, but I think he'll be hooked after the first few episodes. My brother who thinks all anime is like Naruto was instantly hooked.
The show deals with some very interesting topics like identity, ethics, and eugenics.
It's about a brain surgeon who saves the life of a little boy and has to live with the consequences of his decision. Don't worry, this isn't some hospital drama. It's more akin to a horror/thriller like Se7en, complete with religious undertones and themes.
Also, the characters don't all share the same face but with different hair colors. Each face is uniquely drawn with the kind of detail that is unusual for Anime.
This is my recommendation.