You have to play to the rules as they are written, not as you want them to be.
Any vote for a third party in a US presidential election is a vote against your preferred major candidate . It's really really simple.
It's a very sad indictment of how broken their electoral system is but reality is what it is.
This time all he might need is a couple of dodgy decisions in some swing states. "Oh my the Dems are cheating well the wonderful governor of state X can overturn the election results and the delegates can vote for who the think the people really want."