Rome: Total War has gotten rave reviews. It's kind of a cross between the Civilisation series and Command & Conquer. You can stick to the strategic side and just deal with everything from a world wide view, or take charge in specific battles.
The new Lord of the Rings: Battle for Middle Earth also got good reviews.
Has he ever played the Axis & Allies board games? If he did,
this might interest him. Haven't heard too much about it though.
Myst is a great game for puzzle solving, but can be very frustrating if you aren't patient or tend to miss details. And you can die, if you choose the wrong path.
goates