The fact that this pilot landed successfully on a "runway" only 10m wide - about the wing span of his aircraft - with the added distraction of a large passenger jet unexpectedly taxiing underneath him when he was about to flare, would indicate that he is not past it just yet.
When he gets his "please explain" letter from the FAA(because this is all this minor incident warrants really), I would recommend that he asks them to tell the airport operator to mark their runway more clearly - at the moment there are no piano keys or even gable markers or cones in use - see previous picture(and just because it is a VFR runway is a pretty weak excuse not to do so).
20R piano keys could do with a repaint too if this hasn't happened already!
In return, he could promise to use all the resources at his disposal before he flies e.g. study Google Earth's representation of the destination airport(s) and work out what each approach will look like etc., and this should be the end of the matter.
As has been mentioned in previous posts, there is plenty at this airport to confuse a pilot and a runway that is hardly distinguishable from its next door taxiway is not helpful.