I think i understood it...
when water vapor meets melting hot iron or other metal it becomes hydrogen... by the oxidation of the metal...
If you look on how the geet is working, and how other methodes work on creating hydrogen, then i think that this cooker is using a bit electrolysis and a red hot waterheater, which also might heat up the steam.
The heater might be of iron, which would provide even more hydrogen.
And yes, he is using alcohol for lowering the burnrate of the flame.
He needs some carbons to do this. Alcohol is a good provider of carbons.
Steve