Are you alone at home at any point and do you have a chance to look at her tax returns? There may be useful information there. (Look carefully at the way it was stacked, pic phone everything and put it back exactly as it was placed.)
Talk to your GC on Monday and lay things out, specifying they the information provided must remain confidential. Ask if the GC has advice or could call UnC.
Is there a lot of stuff that you can’t fill out? What’s your deadline?