Water salt or not DOES NOT BURN ever in any way.
Burning is the 'Oxidation' of a substance , the combining with Oxygen, water is already combined with Oxygen , it is made of Hydrogen and Oxygen, H2O. So another name for water could be Hydrogen Oxide or 'oxidised ( burnt) Hydrogen.
When you burn or light Hydrogen it combines with Oxygen from the air and forms water. Not the other way about!
Another indication that the video is fake is the colour of the flame , yellow, the colour you get when burning a substance that contains Carbon ( like natural gas). When Hydrogen burns in air the flame is colourless , invisible , it gives out UV and IR radiation but no visible light.