Could be a few reasons :
He may have a problem with his electrolytes or a problem with his adrenal glands.
Either way, he needs a blood test. Chefs sweat a lot and need to stay hydrated. Gatorade helps a lot as a quick fix.
Then you have Chefs who over the years , have slowely increased their salt intake to the point their palate has grown accustom to such high intakes that they no longer recongnize they are putting too much salt.
Maybe he is just young and ignorant...