Hi,
If he's not going to use the internet then there will be no real improvements at all for him, except maybe for a boost at bootup that some people noticed (Some saw it slow down though)
It was mainly an update to block holes for hackers, and to bring some functionality to Windows by adding pop up blockers and a built in firewall (again for internet use)
Also is it just me? or does it also take away the version you have at boot up? Mines Professional, and after installing SP2, this dissapears :S
Hope I've helped
*KaGe*