I notice that they expected a non-precision approach at destination. Some, not all, major carriers require all non-precision approaches to be flown on autopilot if the weather is below VMC. If the autopilot fails enroute, and only a non-precision approach was available at destination, you would have to divert to a field that had an ILS or VMC conditions, or use your emergency authority and make the safest decision. Note: For something like this, you may be using the emergency authority, but there is no reason to declare an emergency with ATC.

Joe