Getting a Pressure Ucler in a Nursing/Rehab facility Neglect?

My Dad was admitted to a rehab center bc he fractured his left hip he is 71 years old. He is insulin diabetic and has had CHF and stroke. He was in the rehab center for over 30 days. He already had a bad left foot he was preparing to get the toes amputated. I realized after he had to be hospitalized that he was not given his insulin for one of the doctors did not put it on his chart and the nurses knew he was insulin dependent. They did not change his foot 2Xs a day like it was ordered. I had to cause a big fuss. One day when I was giving him a shower I noticed this sore on his good right heel in April. Here it is in October and we are fighting to save the foot. He is in the hospital now getting a pic line for he will need 6 weeks of IV antibiotics. I am being told that they should of put boots on his feet to protect them means he was not very mobile and would be lying down a lot. Is this neglect on their part. He was discharged from the rehab place.