Would like to use MAC address filtering

[Speedy]

Apple System Profiler (probably under the Apple menu but otherwise in the Applications Folder or do a File menu -> Find) -> System profile tab -> Network Overview triangle -> Appletalk triangle -> Hardware Address. It will be in the form of xx.xx.xx.xx.xx.xx where x is a number or letter. He will need to copy it by hand as you cannot copy and paste info from the Profiler.

And MAC address filtering is a must given his proximity to other networks.