While in a rehab facility recovering from a broken hip, my 92 year old Mom acquired an unstageable pressure ulcer.

It is oval, about an inch and a half by one inch on her heel. The bone of the heel became infected, requiring a hospital stay for IV antibiotics and 3 weeks of rehab. Her vascular surgeon has said it will take up to a year to heal fully. Our family is furious that apparently her skin was not checked in the rehab facility or else they would have found the ulcer before it advanced to being so large & covered in black eschar. Mom has gone downhill since this happened. We are considering suing the rehab facility. Has anyone had a similar experience?