He will definitely lose if he makes any move or continue to discuss delaying the election. That would only give the Democrats some heavy ammunition to use against him. I don't like mail-in voting anymore than he does because it increases the risks of voter fraud. Look at what is happening in two congressional primary races in NY that did mail-in voting. Because the envelopes were postage free, the Postal Service does not put a date stamp on the envelope and election officials are trying to determine if the the ballots were received before the deadline. It's been more than three weeks since the election deadline and still no winners can be announced.
This is very similar to the 2000 election when officials in Florida where trying to determine how a voter voted by the whole "hanging chad" fiasco. Democrats were attempting to give more votes to Gore because even though a chad had been pushed completely on ballots for Bush, the voter really was really casting a vote for Gore because the chad from him was "hanging."
There are too many ways to allow the Dems in swing states to cheat with mail-in voting. The can simply ignore those ballots with votes for Trump or claim those ballots were "late." If you recall, Democrats in Miami wouldn't count the majority of absentee ballots from military members, claiming that they were received after the deadline, even though they were received before election day.
I have seen reports where in Democratic strongholds absentee ballot applications were sent to addresses where those voters no longer live and hadn't lived for years. One person claims to have received applications for four different people. What's to prevent someone who received all these applications for people no longer living at their address from filling them out and sending them in so the can vote multiple times using other people's absentee ballots.
Dems find it totally acceptable and within a person's rights to go out in masses to protest, but not stand in line to vote. That is so hypocritical and the GOP needs to really hammer on that.