The instructions issued by the second approach controller were not complicated, but the pilot had difficulty flying assigned headings and altitudes. The controller also did not immediately detect some of the unusual maneuvers conducted by the pilot or recognize that he was perhaps suffering from spatial disorientation until the pilot explicitly said so. Instead of simply issuing a single heading and having the pilot climb a few hundred feet back into VMC, the controller asked the pilot if he was able to accept "no-gyro" vectors. The pilot accepted the offer, and the controller then issued turn instructions that required turns in both directions. This excessive maneuvering possibly exacerbated the pilot's spatial disorientation. The controller then directed the pilot to climb in an attempt to get him into VMC, but shortly thereafter, the airplane entered an aerodynamic stall/spin and impacted terrain. When interviewed, the controller was unable to explain the basics of no-gyro vectoring and was unable to demonstrate the ability to effectively provide the service.