This one is intriguing. I very much doubt he will get anywhere near the nomination, but he would be great to have on television as part of the debates, and could be extremely effective on the campaign trail - though not near the posh bits of the coasts unless it's Berkeley or Bushwick, mind.
The party will see him as a nuisance, and if he does well, a threat - and they will pounce on his political history (voting for Trump) to try to destroy him.
But if they were even halfway competent, they would recognise that this is actually an enormous asset to them, and they'd see that he got the opportunity to explain - to as many people as many times as possible - why he ultimately turned against Trump and why even the Democrats are a better option.