As someone whose employer blocks the installation of browser extensions, I am more than excited to hear that! Using the web sucks since that policy has been implemented a year or so ago. Integrated adblock engine would rectify that again.

If he can't even install an addon for a browser, what do you think he can do with DNS?

No company that doesn't allow you to install browser add-ons will allow you to run a pi-hole instance. Not on your machine, and much less as an actual pi plugged into their network. If you did plug an actual pi into the network it would probably reason to be just straight up fired.