I think he meant to say to make sure all the "other" votes are counted. Because I'd be willing to bet almost any amount that the Democrats are going to use this whole thing to "find" some votes that were missed the first go-round when Biden is way behind. No United States election has ever been delayed for any reason; not during the Spanish Flu, not during the Great Depression, not even during the Civil War. But I bet they want to delay it as long as possible to make sure they "find" enough votes.
Mail in voting is an absolute scam and a sham. Voting can be done in person, at normal voting centers, with no fear of spreading the Wuflu. People are wearing masks (which really aren't even needed, imo); so there's no need for mail-in voting. It's just another attempt by the Dems to get rid of the one President who doesn't take any of their shit. And I love that about him.