I think that this is really poor advice, and stuff like this almost invariably comes from the people who own the current model. It's one thing if there's no reason to believe that it will be updated soon, but it's not really a prudent buying decision to purchase something this expensive when we have a scheduled event where it's reasonably likely to be updated within 2 weeks. How major the update is a inconsequential. He may be able to get something better and newer for the same amount or less money in a very short period of time from now.
This doesn't just apply to the Mac-obsessed people, myself included, that frequent these forums, but for the general population who should be educated on their purchases.
It's one thing to wait an indefinite amount of time for an update, but another to ignore the fact that there's an Apple event in 2 weeks. If there's no update at WWDC, then I would say it would be much more reasonable to purchase then, but I would certainly wait and see.