How is he keeping that food piping hot?
Well, you could keep it in warm ovens (of such) at low-levels until just before bringing it out. Not quite perfect.
In the 1970’s, we kept our burgers in steam drawers that were electric - they heated the water. It worked just fine for our customers.
We sold hundreds of hamburgers and cheeseburgers on Saturdays. At the mall (folks may not remember those).
It looked like they had a heat lamp on the fries.