Interesting what the underlying causes might have been. If the pilot started flaring at 100 or even 50, that speaks of a very severe misjudgement of height. Something I would be seriously looking into if faced with rectifying such a problem in someone is where they are looking during the final approach and flare. Some people look at the very far end of the runway which makes them flare high (but often still not as extremely high as 100 feet). Conversely, those who look straight below the nose risk either not flaring at all or doing it late enough to land quite hard. Same or worse goes for those who chase the FD bars without looking outside literally until flare. Also, leaving the AP on until 400 feet is not appropriate for someone with low experience and apparently poor technique. Late AP disconnection with no time to properly adjust to manual flight often results in dire landings among the beginners.
It would be interesting to scroll through the training file of someone like that. If the problem had been apparent for months before this occurrence, how exactly was it addressed? What remedial training was given? Was change of instructor considered? I have a feeling that there was some root cause which was never addressed.