Join Date: Oct 2006
Location: Aiken, South Carolina
Bikes: Rans Fusion/Catrike Road/Bacchetta Cafe'
Any of the major brands will have a reasonably priced hybrid which would probably work well for him; for example, Trek 7200 ($379), Giant Cypress ($349), Specialized Globe ($410), Fuji Crosstown ($349). Prices may very depending on you bike shop.
As far as frame size, that is hard to predict knowing just his height, it depends on inseam, length of arms, etc. For example, I am 5'8" and my wife is 5'4", but we have the same inseam since her legs are longer in proportion to the rest of her body. Also, methods of measuring frame size vary between manufacturers. Your best bet is to take him to a local bike shop (LBS) and have him fitted to a bike.