We can expect to see more of this as the subdivisions keep expanding more and more into what used to be the animals' territory. If we are going to insist on living close to the wild or wilderness we can expect to encounter wild life, not all of which is friendly.
I am glad that the boy was not seriously hurt and had the presence of mind to stand up and draw his knife. It made him look bigger to the cougar. The father might want to consider carrying a bigger caliber or a long gun when walking around in the woods.