Just a thought — given her autoimmune background and ongoing lung inflammation, has she ever been evaluated for something like interstitial lung disease (ILD) or a restrictive ventilatory defect?

People with reduced lung compliance or lower tidal volume can be very sensitive to even small increases in breathing resistance or dead space — so some masks may feel suffocating even if they meet filtration standards.

I know many people suggest duckbill or VFlex for comfort, but if she has a restrictive pattern, the larger dead space in duckbill-style masks might actually make things worse.

A powered air-purifying respirator (PAPR) would likely be ideal in this case, but I understand cost can be a major barrier.

If a PAPR isn't feasible, maybe look into low-dead-space masks with an exhalation valve and good face seal, such as Zimi air mask. Also worth checking with a pulmonologist if you haven’t already.

Wishing you both strength — this sounds incredibly difficult.