The pilot (single pilot, 72yo and 50 years of piloting experience) was the owner of QUICK AIR (ambulances, medical aircraft, rent) besides other three aviation companies
Correct. But this aviation stuff was only his side job. His main job was, until semi-retirement, running Germany's 9th largest plant engineering company. He was an aviation buff, held a pilot's licience and invested money in some local aviation companies, but he was not a full-time aviation professional.