Originally Posted by cam_macleod

Yes there's a *A lounge - several. Visit www.staralliance.com to see the list and locations.

That's enough time to get into the city but not to see a lot of things. The Narita Express train will get him to downtown Tokyo within 90 minutes or so (if I recall correctly), so his downtown time would be around 6 hours before he has to turn around and head out.