Did he go on one of those lisenced tours? Whilst they're all cool and safe and that, it's just not as fun without being a real Stalker and going in the buildings. Mind you, the tours avoid the buildings because the floors are collapsing, and all the wooden stuff soaked up fallout like a sponge.
I plan on visiting the zone in the next two years, probably not legally, but I don't fancy jumping through hoops with the somewhat corrupt Ukrainian government to get a government pass into the zone.