Vlovich is describing the very last race only, where he did place the final bet. He takes her 4k and tells her he’s going to place the bet for her so how much she’ll win is a surprise. The horse he said he would bet on loses the race and then he reveals he actually bet on the winner. So for that race and that race only I do think he just bet on every horse and sleight-of-handed the right ticket to her. Timestamp 35:20 in the video you linked earlier. Right after that he explains how the “trick” worked for all the earlier races, which is what you’re referring to.
It's been several years since I watched it, so it appears I'm not remembering the circumstances of the last race clearly. I remember a race where there were multiple volunteer bettors at the track who were unaware of each other and only one of them won. Maybe that was the second to last race.
Anyway, I apologize for my error in recollection. I sincerely remember the gist of the show being as I described. Another reminder that memory can sometimes be weirdly porous yet not be correctly 'flagged' with an appropriate sense of uncertainty.
