I don't think anyone can give a helpful response to such a vague, open-ended inquiry. Arrive on Saturday, leave on Sunday? The same week, as in 1 day and 2 nights in Tokyo? Or a longer stay? What would he like to see and do? In Tokyo it matters as the "city" is actually a loose collection of smaller communities, each with its own flavor and attractions.
Please look through - or have your friend look through - the extensive threads in this forum and Japan Guide addressing your questions. Come back with some specific questions and information on your friend's needs and desires and we can probably provide some useful responses.
To start off, there are 2 dedicated airport train lines that run every half hour or so from Narita into the city. The Narita Express goes to the central city with stops at Tokyo Station, Shinjuku, Shinagawa and others. The Keisei line has a couple of dedicated trains from the airport to the north-central area around Nippori and Ueno. I like the Keisei Skyliner but there are others. Also, there is a wealth of airport limousine buses into the city, going to Tokyo Station and a number of up-scale hotels. The best option depends on where he is going. Haneda is even easier to reach in the morning, with buses, cabs and the monorail.
Last edited by abmj-jr; Sep 24, 2014 at 12:17 pm