It is definitely ok for games, though it is not a high-end gamers laptop. If his primary purpose is to play games, I would go for something with a geforce go 7800 or above in it (or ati 1800).
That said, the size of the high-end laptops are very large. Too large to easily transport. The graphics in this are mid-range, but defuinitely ok to play 3d games. I am running a very new and intensive game on it called elder scrolls iv. I cannot set it to maximum, but can run it at a good graphical level. For the price (about £940 on the internet), it is a great laptop.
The Acer brand is pretty good. They have a great range of laptops, so you may want to take a look at their website www.acer.com
Buying a different brand is ok too, just be sure it has at least a ge force go 7600 card or an ati x1600 (bit better than 7600) card inside. Good luck!