He appears to be a Trump plant put in place to divide the opposition. Half his platform so far has been "Trump was a great President, Trump is innocent, I call on all candidates to pardon Trump" etc. Not that those things are wrong, but why is he even running against Trump then, when he has no chance of winning.
Why running?
To be VP on a Trump ticket, be in the cabinet, get his name out there as an investment in a political future. Probably a few other reasons.
Until the anointing at the convention it’s still possible Trump could fall. That would be an opportunity for him. He could credibly argue that he has picked up the MAGA cause since he’s been openly Trump supportive.