If he wants low-key, comfortable, solid food with a crowd in 30s+, The Harrison (Italian inflected American). Same for The Odeon (more American brasserie style). I like the food at Locanda Verde (Italian), but it's trendy, crowded, frenetic and the wait could be very long. Terroir is a great place for wine by the glass.
355 Greenwich Street, New York, NY 10013
145 W. Broadway, New York, NY 10013
377 Greenwich St, New York, NY 10013
24 Harrison St, New York, NY 10013