The 4GB model wouldn't have enough space for the game unless he bought a hard drive for it already.
The cost of a brand new XBOX 360 that has a much larger hard drive probably wouldn't be much more than the used console + an addon hard drive.
It's about $60 to $100 for an addon hard drive (some of them have poor reviews) but you can buy a brand new bundle with two games for $250:http://www.bestbuy.com/site/microsoft-xbox-360-250gb-holiday-bundle-with-2-games/1817121.p?id=1219065987015&skuId=1817121&st=categoryid$abcat0701001&cp=1&lp=1
You're also dealing with no Warranty and a used controller. I suppose the Kinect would add some value if you even care.
There may be even better deals around, but don't buy a 4GB model.