I don't think that's a fair assessment. If it is mental illness, it's probably the same illness that leads people to become independent artists in the first place.
He mentioned that he got an offer to work for Nintendo and lead his own team by a rep at GDC, but he turned it down because he didn't understand what they were offering him. I could 100% believe that because I could 100% see myself doing the same thing.
He also later said that the ridiculous behavior was all a viral marketing stunt gone wrong, which, again, I 100% believe because I could see myself...maybe not actually doing it, but certainly coming up with a similar idea to get attention for the project I worked so hard on.
IMO the best thing for him to do is lay low until everyone forgets about him, so that he can release his game in the future, maybe under a different title. Although that might be hard because it seems the Youtube documentary crowd has started to shine a spotlight on him recently (that's how I learned about this guy a few weeks ago)
Also, he did release a game titled "Bob's Game" on Steam, but it was a puzzle game rather than an RPG. I think the idea was that the RPG told the story of a game developer named Bob who was working on a game, and the game he released was the game developed by the Bob character in the RPG. It's a pretty cool concept, and I really hope this guy gets around to releasing the full thing some day.