My relative that's in a wheelchair is a paraplegic, and she has limited (if any) feeling in her feet. The only things I know for sure about her situation are that she didn't tend to the pressure sores when they were just babies so they got out of control; and one of her docs told her that being a heavy smoker compromised her circulatory system and made skin wounds harder to heal. (I won't quote what she said about THAT)