Twin engine aircraft flight instructor reported a critical ground conflict while landing at a non-towered airport. The pilot states the intruding aircraft was attempting to takeoff on a crossing runway that was not the current runway in use. The instructor told the conflicting aircraft to abort and it did. The instructor reports this is not the first time this particular aircraft has caused concerns at this airport.

Narrative

While flying in the traffic pattern for Runway X at ZZZ with a student; Aircraft Y announced he would be departing Runway XX. Another pilot quickly communicated that there were two aircraft already holding short for Runway X which was wind favoring and several other aircraft were also using. Aircraft Y announced he would continue holding short until those two aircraft had departed. When the second aircraft made their departure call for Runway X; my student had announced our base turn for Runway X. Monitoring the traffic holding short of [runway] XX; I saw him roll across the hold short line and start his takeoff roll for XX just after we had announced our turn to final for Runway X. I made an urgent call for him to abort his takeoff and was seriously concerned there would be a low level mid air collision at the intersection of Runway X and XX. Thankfully the pilot of Aircraft Y aborted his takeoff attempt and a collision was avoided; with the pilot of that aircraft then deciding to taxi to Runway X for departure. This is not unusual behavior and the pilot of Aircraft Y has a reputation for departing and landing on runways that cross the active flow of traffic causing a collision hazard on a regular basis. His lack of patience to use the proper runway instead of the runway with the shortest taxi route; or arrival route; and lack of situational awareness is going to kill someone. A control tower would also have prevented this event from occurring.