You need lots and lots of real video of a person to train an AI to make fake videos of that person. So, unless the CFO and the other allegedly faked employees are all youtubers, there’s very good reason to consider more plausible explanations.
To your point, you are correct. There are lots of stupid people. This includes people that will blindly believe that AI can just magically do anything and not even consider simpler explanations for things like this.
I think it was just last year there was a story about some school official claiming to have been duped into paying scammers millions from the schools funds, only to later have been caught making the whole thing up in an attempt to steal the money. (Maybe somebody remembers enough to find a link) So it’s not remotely far fetched to think that’s what could be happening here.