This is why early voting is so important this time around, those early votes will be counted and made official. However, Election Day (week) shenanigans will require a recount and be done on paper ballots, with military on watch, blocking out illegal voters and ballot box stuffing.
This would show 2 things, how totally corrupt and rigged our elections have been for decades, and to prove without a shadow of doubt that the country has President Trump’s back in a “Too Big To Rig” 50 state landslide that can’t be disputed. Giving him his mandate, and a perfect example as to why we need election reforms.
I've heard him say quite a few times at rallies and other speeches that "we're not going to let them" steal this election.
EDIT: I haven't heard a peep about the mail in ballots either but he sure encourages early voting. I did mine a couple of days ago and brought in two more that wouldn't have voted otherwise (I'm no Scott Presler, built it feels good!). I have more lined up for next week.