Stanley worked for NASA space program at one point.

Not a good sign, really.

.. links to patents ...

Patents does not mean that inventions is useable or even work at all. In no way patents could be a proof of invention. You could literally write any garbage in patent application and if you pay patent fee, if that garbage laid out in application according patent office rules and nobody else filed same patent you will be given a patent.

his design also had a resonant cavity or shockwave cavitation chambers,

It absolutely does not matter, really, how you provide energy to destroy H2O molecule bonds. If the reason of bonds destruction is cavitation, shockwave or whatever, then, you should spend at least same energy to create that cavitation, shockwave or whatever. You just add some intermediate step in energy utilisation and so add some losses on conversions. Breaking water through cavitation, shockwave or whatever initiated by electricity will be just less effective than direct electrolisys.

Theoretically, you could take some additional energy inducing some kind of, say, cold fusion in water, but there are at least two problems: at first, all LENR experiments including "classic" cold fusion show that you spend more energy to force reaction than you will get from it. Second, you need heavy water, D2O, not regular one. And heavy water is very expensive, there are no any sense to run a car on deuterium-oxygen mix because a songle trip to supermarket will cost you much more than all gas that you will burn in lifetime.

Things are not work by magic. Everything is connected and if you have to provide some energy to some process, you have to source it somewhere. If there is no any additional process that could be a source of additional energy in your device,you have to provide all of it.