Flight Instructor on training flight during landing rollout reported PC-12 aircraft attempting to land in the opposite direction.

Narrative

I was 10 miles to the NW to enter the pattern at ZZZ. There was a PC-12 who had called for Tower and many people told him that Tower was closed and there was an active NOTAM for Tower being closed. The runway in use was Runway XX at ZZZ; so my student and I proceed to enter on the 45 for the left downwind for Runway XX. I make a 10;7;5 and 3 mile call out saying that I will enter the left downwind for Runway XX. I proceed to enter the left base for Runway XX. At this moment the only traffic I am aware of is airplanes entering the pattern because they were talking on CTAF. My student then proceeds to turn final. We landed on the 1000 footers and as I look up I see the PC-12 landing on Runway XY. The PC-12 performs a go around. I queue up on CTAF telling everyone not to land because of the PC-12. After this happened the pilot of the PC-12 queues up on CTAF finally making traffic calls. He admitted to the being on the wrong frequency. After I landed and the PC-12 had landed I confronted the Pilot and he had no remorse for what just happened. The PC-12 had 6-8 passengers on board.