The author of the article seems to mention how heroically he ignored all of the educated naysayers. We'll see how heroic he sounds when his children are dead and he's in jail for criminal negligence.
Seriously -- we have REALLY warped senses of what is dangerous. What is the scenario for the pool "collapsing" when his children are playing in it? A 60 pound girl waves her arm displacing perhaps 2 pounds of water at a few inches per second, which then pounds the surrounding concrete to dust, causing it to fly at supersonic speeds into the water, in the direction opposite the water pressure? I didn't exactly do so great in physics but I'm finding that sort of unlikely.
The most likely failure -- his pool springs a serious leak. The garage gets written off. Oh well.