I fear that Sanders and many of his supporters don't realize that Hillary is INDEED his biggest "enemy". Showing solidarity, patting each other's backs and agreeing with each other at the debates (as nice as it is) WON'T help Bernie, I am afraid.
His campaign is outspokenly "non confrontational", he's avoiding even addressing his rivals and reasons why better not to vote for them. And this could ultimately cost him. Hillary *is* his biggest obstacle, that's how I see it right now.
Bernie believes that his ideas stand on their own merits. He doesn't need to tear down the opposition. That and continuous scandal mongering are best left to those who have little else to offer.
He says "This way is better". That's a huge contrast to current Repub raving which boils down to "They suck". Given their ideology & past failure, it's all they can say.
I don't think Bernie intends to win but rather to shape the direction & platform of the Democratic party, remind us that the roots of our ideology lie in the New Deal.