This is very similar to an issue that happened with an arcade company called Ram controls. The guy promised people he would build brand new Star Trek vector cockpit arcade games for 3K or so, and it all seemed legit at first. The guy actually produced some of the parts, for instance the steering control, PERFECTLY and was selling them on his website. Tons of people bought them. He reproduced other controllers and at first, everything seemed fine.
Then he started doing strange things, like saying if you sent him 500 bucks right now, he'd give you 1000 credit on his website to buy things.
Eventually he just disappeared with countless dollars he'd swindled out of people. It was the same kind of scenario where it seemed like he had all the best intentions at first, and then went into straight up scammer territory and was obviously stealing and lying to people. A few people got phone calls from him telling them that he had their Star Wars game finished, he just needed the $600 to ship it, or whatever, or for them to pay the other half of their preorder, etc. After they paid of course they never received anything.
Of course there was never a fully built game, you'd have to reproduce artwork, the wiring harness, build unique 1 off cabinets that were only for that 1 game, make the plastic seat, make all the brackets, the controller, recreate the game boards, create a new vector monitor. The whole thing in hindsight was ridiculous but yet tons of people sent him their money.
Kevin had a working prototype you could play, so it's easier to see why people would believe he could pull it off. Lots of the parts were off the shelf, and the other stuff he actually did make for the prototype.
In both scenarios, I think you likely have one of two things going on, unfortunately. A drug addiction, or a gambling addiction. Both can facilitate a small fortune disappearing with nothing to show for it. Even if Kevin built 10 games, spent money on EOD, flew all over the country, there's a huge, HUGE chunk of this money that is either still sitting in an account somewhere, or was blown on drugs or gambling.
I hope to god it's sitting in an account somewhere!