This was a personal stunt done by a minor and allowed/encouraged by parents. The story references:

1) Private charter of an A300 search jet that had to make a 4700 mile round-trip. Crew, fuel, coordinated response staff/facilities. TAS - are we talking $500k plus?
2) Three rescue boats (and crew) en-route in 30-foot seas in winter gale conditions in open ocean. All at risk themselves in hardship conditions. Are we over $1 million yet?
3) Echoing Jeremy's post above: The article says "renowned Australian round-the-world sailor Ian Kiernan said Abby should not have been in the southern Indian Ocean during the current southern hemisphere winter."

Is it too early to claim a happy ending?

IMHO if you're going to take deliberate reckless and extraordinary risks (or allow your minor child to do so) you should be responsible for the consequences.