It was a joke.

Although it's quite possible your colleague has that many miles, the others are right -- a large chunk of the airline points probably came from bonuses on flights. It's not the same as what we call butt-in-seat (BIS) miles. It's still pretty impressive, though. The AmEx points seem reasonable for someone who travels and has a lot of business expenses. There are quite a few FlyerTalkers (as well as consultants I know) who run all of their expenses through a single card and rack up beaucoup points.

Last year I estimated how many miles have passed through my United Mileage Plus account in the 16 years I've been a member. It's at least 3 million miles! I've been a Premier Executive or 1K for nearly all of my 1.1 million United miles, so I've accrued a 100% mileage bonus on those flights. Then there are the credit-card miles and other miles & bonuses that have been offered by UA and its partners. And I'm not even a big-dog corporate traveler.