Depends who gets onto the board. There are probably a lot of forces interested in ousting him now, so he'd need to do an amazing job vetting the new board members.
My guess is that he has less than a year, based on the my assumption that there will be constant pressure placed on the board to oust him.
What surprises me is how much regard the valley has for this guy. Doesn’t Quora suck terribly? I’m for sure its target demographic and I cannot for the life of me pull value from it. I have tried!