First, all the credit and praise in the world to you and the Mrs for helping this young lady.
Also x2 what simon and fink said. Its never demons. Its also never god.
As a side note auditory hallucinations are far more common than most people realize. Hearing voices is on the extreme end but a great many people hear things that are not real. Often its a framiler noise or a noise that your brain expects to hear at particular place or point in time and your brain, in expectation, fills the noise in even if it dosent actually occur.
People with cochlear implants report on the phenomenon. If they hear a song they knew before they experianced hearing loss they hear song in full detail. If its a "new" piece of music. One they wernt framiler with prior to hearing loss, then they hear it only through the limited ablity of the inplant to transmit the sound. Hearing the music in its full detail is a form of auditory hallucination, albeit a desirable one.
in any event, a long rambling post to simply say that these events are not at all rare or demon insipred. And again, well done by you and the wife for offering help!