Air Traffic Control Fully Certified
Confusion; Situational Awareness; Physiological - Other
ATC Issue All Types; Aircraft Equipment Problem Critical
General Declared Emergency
Aircraft; Human Factors; Weather
Bonanza 36 departed ZZZ IFR climbing to 3;000 [feet] on a coordinated 040 heading. Upon reaching 3;000 [feet]; the pilot requested higher stating he wanted to get out of the clouds. I told him I could send him direct at 3;000 [feet]; or turn him east and climb him to 4;000 [feet] shortly. He chose to fly the 040 heading and stay at 3;000 [feet]. At this point; I noticed on the STARS he had turned to a northerly heading and was correcting back to 040. I also noticed his altitude was high. A B737-800; a departure off ZZZ1 was level at 4;000 [feet]; talking to Departure South. Departure climbed the aircraft to 5;000 [feet] which is normal practice for some. At this point; I noticed the Bonanza in a right turn northwest bound and climbing; conflicting with the B737-800. I told the pilot to descend back to 3;000 [feet] and turn back to the right. That is when the pilot told me he was having problems with his auto pilot. I informed Departure South of the aircraft and they began working 'around' me. I told the pilot the only tops report I had which was 80 miles east of 8;000 [feet] and he said he wanted to go there. I issued a 090 heading and climbed the Bonanza to 8;000 [feet]; coordinating with other sectors.  The pilot continued a left turn back toward ZZZ1; so I stopped all departures off ZZZ1. I asked the pilot if was having problems with the directional gyro or the auto pilot. He restated the auto pilot; however he would not maintain an altitude; nor even a constant climb or descent. I asked if he wanted no-gyro vectors and he said yes. I issued a right turn; but he continued left. Assuming the pilot had spatial disorientation; I told the pilot to level the wings; and not look out the window. I told him once he was flying straight to see if his directional gyro and compass were aligned; which he said they were. We started to discuss options about returning to the airport; or any airport and the pilot agreed. However; he was still flying erratically. I got him level on a southwesterly heading and told him to descend; and that the bases would be about 3;000 [feet] or so; and that the highest obstruction was about 1;500 [feet] over downtown. With the help of a fellow pilot/controller; I told him to lower his gear and reduced manifold pressure to 18 (1800) to establish a gentle decent. About 7 miles north of ZZZ; he broke out of the clouds and I told him to fly southbound for a downwind to Runway 4. At that point; the pilot asked if he could turn on course to ZZZ2 VFR! I told him he could; however; there was a line of storms extending [through the South] with low IFR ceilings and suggested he land at ZZZ to examine his options. He said he was fine and would continue on to ZZZ2. I told him to maintain VFR and fly on course. He was handed off to Satellite.  While I did everything I could think of to assist the pilot; and enjoyed the assistance of several other team members helping me and providing advice; this ultimately rests on the pilot. He was apparently capable of IFR flight; but when he realized he had an issue; he should have put the aircraft on the ground; reassessed his options; and determined if flying that day was appropriate. I am not sure there is anything else we as controllers could have done to assist him.
TRACON Controller described a pilot disorientation event when the pilot requested to get out of the clouds; was assisted to VMC conditions and then requested VFR to his destination.