Re: The autopilot is not an autopilot ?
A bit OT there, but "Because it was dark, had no visual confirmation" means your flying on Instrument Flight Rules. Key word being INSTRUMENT there.
The first officer was pilot flying and interpreted the situation wrong, and pulled the aircraft into a stall.
It also didn't help that the Captain tried to control the situation, but resulting in both pilots trying to to do opposite actions, which in an Airbus of the type, just cancels each out (one nose down, the other nose up, resulting in a neutral position, which was already up). You do get an aural warning "Dual input", and a red light saying the same on the glareshield, but both ignored it, for the most part of the way down. In other words, CRM was part to blame.
The aircraft was perfectly flyable otherwise...