Even after deletion, Wikipedia keeps the history of editions. If Wikipedia's moderators got to remove the edition history as well, it won't suffice, as there are many backups of Wikipedia out there, because Wikipedia itself is open and easily downloadable (just a couple of gigabytes). Also, there are Wayback Machine and Archive Today.
The desperate order to "delete everything" just confirms how managers and CEOs are absolute unaware of how tech and internet actually works.
Well, he can possibly know people from Deep Web and use platforms inside I2P, Freenet, Yggdrasil, GNUNet or Onion (Tor) network (although I don't recommend this one, as it's poisoned with several FBI-backed nodes) to chat about it.