He doesn’t have to prepare. They already have footage of him at a podium. All they have to do is dub the words and lip sync.
There is software today that is so sophisticated that it can make Mikail Gorbachev appear to be reciting the Gettysburg Address. Piece of cake to use it to make it look like the old decrepit geezer is saying coherent things. A brain-dead public will believe it.
Of course they are going to do it! The criminal organization that falsified the election results would not hesitate one moment to create a fake speech by their man.