Of course the CEO is in on it. He probably set it up in the first place. How did he not recognize his own COO on the call?! Even with the voice "digitally altered" (?) it should be trivial to recognize someone you work with every single day. And if the CEO had been in contact with the YouTube person before he also, at least, should have understood that this was not him.

If you search for the CEO's name on Google Images, you get a wall of photos with the exact same broad, fake smile. What a character. It's amazing what some people can get away with.