I'm confused - the legal rep of a website is posting things on other websites about someone who writes for their website, but doesn't put that announcement on their own website? Do we know that person is actually in that position?
Surely if they do have proof of something that would be the first thing to do: put it on your own website and announce that you have severed ties with him.
I have zero information about what may or may not be true, I wouldn't be surprised by anything and thought there was more behind his recent video, but what I've seen here does not meet the criteria of being "proof". Claiming you have proof of something in a video is an accusation, it's not evidence.
UPDATE: He's confirmed the source and the content. She was the legal rep for the JW Watch website and advised him to come off social media. Instead he ignored her advice so she understandably chose to resign, as did the producer.