patricej

i confess to being tempted to arrange things so i can do it all sitting down.
however, i keep my cutting and pressing surfaces separate from my sewing surface.
i always advise cutting while standing up if it's at all possible - even if the person can stand for only a few minutes at a time.
it's easier to measure and cut accurately.
and ... we spend so much time sitting while working on a quilt, we need to get up and move around from time to time.
it is not good for the spine, hips or knees to remain too long in the chair.

if a person truly has a physical disability that makes standing to cut impossible then there'd be an obvious requirement to find a way to cut sitting down. it would take planning, experimentation, and patience because it's extremely difficult (bordering on nearly impossible) to get an accurate measurement or cut while sitting.

if that person can set up a configuration that provides the proper line-of-sight for accurate measures ... and
if the configuration works in combination with the cutter's arm/hand/cutter position and reach to enable accurate cuts ... and
if that configuration also allows the person to maintain proper posture while cutting ... then the person can remain independent. otherwise, she'd have to limit herself to pre-cuts; pay somebody to do her cutting; or hope she can find somebody who will do her cutting for free or barter.