My understanding is that he supported the concerns about fraud with a specific lie (maybe more than one) about how the state authorities are sending out ballots to everyone, whereas they are only sending them to registered voters.

This could, and presumably is intended to, mislead people on both sides of the political spectrum.

Assuming for the sake of argument that someone could be trying to promote a fundamental truth using lies, it doesn't make it sane to trust or acquiesce as a result of lies.

Maybe in our brave new world, disbelieving in something because it is supported with lies is an example of an ad hominem fallacy?