Great job by both passenger and controller-instructor.
As for the difficulty, I did "sim experience" flights during otherwise unused A320 simulator slots a while ago. Those were sold to the public and while some customers were avid flight simmers who got it as a treat from their loved ones, a good many were absolutely new to aviation (other than flying as a passenger). Most managed a survivable landing within their 20 minutes of flying (3 sharing a 1-hour slot) flying a manual ILS ILS with autothrust. I dare say that if you have the option to fly a coupled ILS chances for a survivable (if not reusable) landing are good, even without autoland. The main issue would be communication and remaining fuel to talk the newbie passenger-pilot through the required setup.