First for that price range you can find a decent selection. Vision, Burley & Rans come to mind right off.
As far as fit is concerned about the only thing he'll need to be really concerned with is crank arm lenght. A 'bent is very adjustable when it comes to distance between the rider and the crank set. On most you can adjust both the seat and the main boom tube. Unlike on a wegie it is just the seat height.
some other concerns is wheel size and long, medium and short wheel base models. Try to find a decent recumbent dealer in your area for more help.