Yeah, might work if the starter he used was fully isolated, but I kinda doubt that was done.

But it always kinda trips me out how even experienced bakers think sourdough has to have some kind of magic seed to work as sourdough. It doesn’t matter what you start with, the flour you feed with, and the environment you’re in are going to have yeast already present, so you’ll eventually end up with whatever is in those being what’s doing the work, not what was in the inoculation.

Same with the lactobacilli, whatever strain is present locally is going to end up as the working strain.