Haven't been there in a while but I always like
going to Zen Palate. There are several locations.
Vegan "asian style" but not all low fat.
If he is on an expense account, and likes Japanese
food, order the Vegetarian Kaiseki at Sugiyama. The
only place I've ever had such food. I think you need
to call ahead for the Vegetarian dinner, but really
worth it.
Aiko