I don't think he meant how long will he stay healthy, I think he meant how long will he keep up this level of play. Am I right?
I could only imagine that he would keep getting better, but sooner or later, if they don't get a supporting cast around him to take some of the heat off, either he will get hurt or defenses will start keying in on only him and forgetting about anyone else. Someone will eventually figure out how to stop him if he's 80% of the offense every game.