Your G tolerance will decrease with fatigue and as you dehydrate. It will also be affected by G onset rate, exposure time and the position of your head - it's possible to disturb or even close the carotid blood vessels looking over your shoulder for example. Whether or not you grey-out partially or completely will also be affected by how effective your Anti-G Straining Manoeuvre is and how timely it was.
So - not on the board and no idea what happened other than we lost a great bloke. But yes, it is more than plausible that one could A-LOC or G-LOC in a break to land having not been unduly affected by G during an aerobatic display.
RIP Egg man old chap.