I'll grant you I was misinformed on the latter, but can you point to some source on him not working for Mozilla at all anymore? Nothing I can see says anything but that he stepped down from the CEO role and his board position on the Foundation (which would be where he could still have a say in the running of Mozilla, I don't think it was the goal of the boycott to have him leave the Foundation board so it seems a little excessive to me).

That is a shame if so, as his technical contributions are still clearly valuable.

[edit] https://brendaneich.com/2014/04/the-next-mission/ answers my own question.