I agree: NOTHING IN WRITING. It's the same as handing your enemy a box of bullets.
Using scriptures to debate still brings on the "A" label, so if you go that route you must be inordinately calm and not appear to be upset. Just ask her opinion on the discrepancy and see where she takes it.
UNSEEN made-up illnesses are the best. Migraines bring on great sympathy (perhaps triggered by mold in the kh ductwork? someone's perfume?). Irritable bowel or repeated bouts of diarrhea bring instant sympathy. Depression is a hands-off area for the elders so that works if you are not overly cheerful.
Best wishes for your fade/withdrawal journey!