My theory is he was a Democrat plant/pawn. He had no idea he was going to win and does not know how he won. They paid for him to run then rigged the ballot boxes to test to see exactly how to handle the media and deflect an investigation into the voter fraud. This was a practice test for the big fix in November.
This is the only thing that really makes sense to me.
The idea that primary voters (even dems) went to the polls then just spontaneously decided to vote for someone they did not even know is simply not plausible to me.