Hopefully the use of the gangbar is just a reporting error, as I am astounded that the Captain (or any half competent pilot) would do this in IMC and remove all electrical power, and thus all instruments.
That is suicide in IMC and reflects no system knowledge and dangerous training deficiencies if it is actually the case.
I agree with TorqueTalk, they must have had some sort of visual reference or they would have been dead.
The ONLY time to use the Gangbar is on the ground.