Fractional Captain reported a critical ground conflict; with an aircraft landing in the opposite direction; at a non-towered airport.

Narrative

Flying into ZZZ. Ceiling broken at 4000. Winds were 060/15. ZZZ approach vectored us for straight RNAV approach Runway XX. Prior to FAF; we called the airport and cancelled IFR. We have been monitoring CTAF for 75 miles out. I made the initial contact with CTAF 15 miles out while being vectored. 2 other aircraft's were doing touch and goes. Aircraft Y was doing a practice approach on runway XY with circle to runway XX. I kept giving position reports every 5 miles. The Piper Warrior kept on his approach. Missed approach instructions per approach were climb straight to 4000 and hold at ZZZZZ. Since we were cancelled; go-around would be to stay in the pattern. We continued the approach and landed on runway XX. We could see the Piper coming straight at us the entire time. In fact; the piper didn't circle properly for a single runway airport. He flew right on top of us on landing roll out. As we exited to the left; we could see him what I would call:'the most cowboy approach I have seen in my career'. He barely joined a very low altitude downwind; overshot final with very high right wing. Almost a perfect cross controlled stall situation. After exiting the aircraft; the line personnel comment on that aircraft right away. Both line personnel are rated pilots. They said the aircraft is at a local flight school and they always do this. I called the flight school and discussed with the owner. He wasn't very receptive. He said the aircraft belongs to another operator. Line personnel used to be an employee of the owner and he owns the airplane. He has two bases for his flight school. I tried to explain the danger of go-around and doing opposite direction practice approaches without being on a code with ATC. He didn't care. I spoke with the TRACON and they confirm that they do this all the time and its a huge problem for everyone.I suggest reaching out to facilities and others to investigate further. Also; notes should be added to explain the flight school practice approaches in the area.