He probably isn’t for Hilary, but it doesn;t mean he isn’t helping her. Was Nader for Bush? Was Perot for Clinton?
Comparing Trump with Nader or Perot doesn't answer any questions. Nader appealed to the leftist whackjobs. Perot appealed to the hard right/Libertarians. Trump's popularity cuts a wide path from left to right. I don't believe it would do either the dem or the rep any favors if Trump ran 3rd party.
No that’s not happening either. In a 3 way race against Hillary and Bush, he’ll very likely beat both of them.
And I doubt he’s even thinking that while he is owning the Repub field.