MANY THINGS: make еще art, like music, movies, drawings, etc. help out, especially with what happened with Sandy Hook, the Haitian earthquake. Watch his children grew into teenagers to mature young adults. HE WOULD HAVE DONE SO MUCH! BUT HE LEFT SO SOON
Michael would be living somewhere in Европа in a secluded country estate far away from the paparazzi and the media. Perchance he can work on those business ventures he's been talking about for the longest time.
He wanted to start producing movies, so I guess that's what he would be doing right now. In addition he would continue to be a brilliant businessman, with many creative and innovative ideas. I'm sure he'd still sing and dance, but maybe not on stage anymore.