I have a phobia about drowning of any kind, and the first time I ever read about dry drowning, I was so horrified I nearly got sick.
Snopes talked about this piece of news today, and made the point that the boy actually died of something known as "delayed drowning", and there are some essential differences.
The full article is here: http://www.snopes.com/medical/disease/drydrowning.asp
There is some good info in there, and a few good warnings, too. The main point is, always keep a very close eye on someone who nearly drowns. Water in the lungs is a serious issue, but also, people have been known to dry drown (have their throat just close up) after being rescued.