Do us a favor and don’t pretend to understand the physics of it. It is pretty clear the guy doing the jump knows more about it. When Kettering did this he got withing 20 or 30 mph and did not burn up. There is not much air up there to heat you up. To say nothing of the amount of COOLING you get from -90 degree air blasting past you. Plus the heating at mach 1 for a short period of time is not that much. Compared to the thermal undies he needs to survive the cold assent that heating is nothing at all.
But anyway, I'll hold my opinions.
But you do me a favor and get back to me when this dude fails or dies in the attempt. Until then, nothing posted on this thread by anyone is worth a damn.