He is surely very evidently mentally ill.
This is a man who, to be fair to him, has been beneficially bullish and iconoclastic in the WP community's favour for decades, as well as writing a big chunk of what was "early modern" WP. Before he came unglued.
The fact that he looked, sounded, talked the way he did, was involved, put his own money where his mouth is, and was press-available to the extent he was is a lot of why WordPress was ever taken seriously. Given the level of control he has, it was used pretty judiciously for the longest time.
I am of the opinion that his broad charge against WP Engine was valid; I think he handled it insanely.
But as I say, he has come unglued. I'd be surprised if he returns to the job. I wish him well as I think anyone who has made money because of WP should. Things have gone wrong but there was a long run of things going remarkably well.
I do think this was overdue, for everyone including Matt, even though he evidently cannot see it. I hope, but am not hopeful as it were, that he sees that this is a message from the world to change track. I would instead expect to see a bit of revenge.