This RF water trick and fusion are two different animals. In the case of the water, you are just bonding and unbonding atoms. You take a stable, low energy molecule of water, put energy into it, and you get two high energy hydrogen atoms and one high energy oxygen atom. And when they bond back together (as in combustion), you get back the same amount of energy that you put into them (minus losses due to inefficiencies). With fusion, you are actually converting matter into energy. You are feeding the reaction some energy in the form of energy (to keep it going) and some energy in the form of matter. You get back a lot more energy than you put in, because the matter has been converted. This is not the same as simply bonding and unbonding atoms.
In the least it's a novel form of electrolysis but they're not publicizing it as such.
From what they're claiming it could be the RF is doing on the molecular level sort of what neutrons do at the atomic level in fission reactions. It could be the specific RF is used as a highly efficient catalyst for weakening the di-electric bonds in the water molecule allowing an energy state transition which produces more energy than required by the catalyst. In this case it's the energy from the H and O recombining rather than U breaking down.
If this was the case though he could just scale it up to run a small generator to produce the RF and his "look at this" demonstration would be a closed system with a net power output. To my mind the only thing which can do that to date is atomic fission. So yeah, until they publish the numbers it's probably just a new form of electrolysis and desalinization.