I feel for you gness - there is a school of thought that says "any pressure sore is, by definition, bad nursing care".
All I can say is that the people who say this have never worked with people with late stage dementia - fragile skin, not a jot of compliance with care (actually very often deliberate anti-compliance) plus highly complex co-morbidities and drug regimes. Sores are not inevitable, but they are damned difficult to avoid completely.
Freed from the constraints of the (slight) political correctness I had to uphold as a professional, I can say (as a dave) that I just hope your wishes for a speedy end to your mother's suffering are fulfilled.
Rowan - please tell redman to get better quickly - there's a pint in the pump for him at the PO Vaults and it needs drinking before it evaporates.
dave xx