On this occasion the instructor did the flare for him, but he flew the rest ...
Not exactly difficult to believe for a PA28 ... actually many people could do this (without any advance MS FS play-time), provided only that they had a good instructor coaching them.
chaps who come along for trial lessons who have played around on a serious basis with PC flight sims do seem awfully good ..... although they tend to fly by instruments .....
Which is exactly why MS FS is a bad idea for most people: it teaches them to look inside rather than out. You might try covering the ASI and altimeter, that should break them of this terrible habit.