iirc, the Apple download thing for WoW also had WowMatrix available for download... >.>
Anyway, if it's legit, then it *wouldn't* be mac-specific. And it *wouldn't* be able to interact with the minimap. The way things like Carbonite work (for the punks module/showing other faction) is that the many users of Carbonite communicate with each other when they come across a toon of the opposite faction.
Ask your friend if his "addon" was installed in - and ONLY in - the Interface\AddOns folder. If not, tell him he can kiss his account goodbye.