Yeah, I'm sure she'll continue on with HP canon from beyond the grave. Seems plausible. That's what Ouija boards are for, right?
But in all seriousness, it's not like HP will die when Rowling does. Its legacy will live on and later generations who read it will continue to love it and keep it alive. Just like how Sherlock Holmes is still alive despite Doyle being dead for 90 years. I'm sure Hollywood will keep making HP adaptations long after Rowling is gone since it's sure to be profitable.
This is a bizarre question..... JK Rowling is still alive and she finished the book series a few years ago. There's been a film series which finished afterwards and that one is also complete. This is common knowledge.