Sure, that's plausible... a facebook exec so dumb that they're using their personal ISP connection to run a VPN for others, and even dumber that they don't notice or don't care about a massive amount of torrent traffic through that VPN.

It's not really a VPN for piracy purposes unless it's a commercial, no-log VPN. Since when a VPN is used to move the point at which traffic enters the internet, the owner of the VPN exit will be held to account.

They can try to claim they were running a "private" VPN and gave random people (from reddit and discord) internet access through it. They can try to claim they don't keep logs. Meanwhile, for a facebook VP with suspected activity tied to facebook corporate, the rightsholder will subpoena every digital device in the person's home, depose all their family and close friends, subpoena their facebook email...