The standing high altitude jump record was set in 1962 from 100,000 ft, IIRC. Of course, that was part of the early NASA manned space program.
Got a really dumb question: have there already been experiments in dropping objects from near space & measuring reentry velocity? Well, of course there were - they had to determine air friction surface temperatures to calculate how much heat shielding was needed for the space capsules.
In other words, does our high altitude jumper already know for a fact that a supersonic reentry fall prior to contact with lower atmosphere is indeed possible?
Anyway, good luck & Godspeed to him and his venture.
Of course he does. Joe Kittinger, current record holder, is on his mission control team!