In years past, whenever an STC became a sim instructor (such as loss of medical cases), they were allowed to conduct regulatory events in the sim for one year after their last flight in the aircraft or the expiry of their letter of authority as an authorized examiner, whichever occurred first.
Sounds like CAD has yet again changed the rules in favour of CX to allow these individuals to re-qualify as STC's in the sim only.
Of course none of these sad pricks will decline the offer to conduct PC's, it will be a big boost to their egos since they clearly have nothing else going on in their lives.