looks okay for the money, 2009 is only about £185 so that's pretty good.
big chain ring and a free wheel not a cassette hub, but that might not bother him, but obviously a nice small chain ring (or sprocket i think the sprogs call em) is easier to keep off the coping.
depends what he wants to use it for i guess.
does he only want a Mongoose? and is that budget fixed?
if he's going to be looking to upgrade he might be better spending a bit more from the off.
also, if you can find any left 2008 bikes were better value than 2009 bikes generally.