Pick him up a good audio interface and one or two microphones.
AUDIO INTERFACE
He probably already has USB ports on his computer, so stick with a USB interface.
I would recommend something like the
M-Audio Fast Track USB:
http://www.sweetwater.com/store/detail/FastTrackUSB/
MICROPHONE
Now, one could plug a guitar directly into the interface, but the results of running direct are far less sonically pleasing than that of a mic'ed up amp or guitar. I would strongly suggest a microphone for better results and you would kind of need one for vocals anyway.
If he's primarily an electric guitarist, check out the
Sennheiser e609. I find to be a very versatile mic for mic'ing guitar amps/cabs and can be used for drums and vocals with great results as well.
http://www.sweetwater.com/store/detail/E609Silver
If he's an acoustic player, I would suggest a condensor microphone, but you would need an interface/preamp with
phantom power in order to power the mic.
AUDIO SOFTWARE
Just about all low-cost interfaces come with some sort of trail or stripped-down version of some software, but I highly recommend using the shareware audio application
REAPER. This can be downloaded at
http://www.cockos.com.