This is not an Aircraft or Airline specific requirement that he is talking about. A number of aviation authorities dictate minimum visability requirements with regard to instrument approaches and equipment available.
As stated above, CASA (Australian) says that without an 'autopilot' coupled to flightdirector, the approach the minimum visibility for the approach is 1200m even if the published minima is 800m. I suspect that whatever authority this 'trainer' was operating under has a similar requirement.