It's not a publicity stunt. The defacer has a zone-h profile with over 800 other sites he's defaced. And TurkStorm is a group of about 10 little Turkish script kiddie wanna-be hackers.
And it's not exactly what I'd call a "hack" either. It's a relatively simple SQL injection and his programmer should be fired for allowing it to happen. It's a very basic security hole that anyone with experience should have known to patch.
Assuming that the programmer has a backup, his site *should* be back to business as usual as soon as the programmer wakes up and turns on his computer.