My husband was in a hospital in Pittsburgh. While there he ended up with a pressure sore so bad he had to have surgery at another h. Who do I look to?

Jim went to Presbyterian Hospital in Pittsburgh for surgery on a brain tumor and to have a shunt put in. He was in there a good month due to several complications. While there the nurses did not take care of him properly and they ended up sending him home with a bed sore. We didn't realize how bad it was until we got him home and the in home care nurses saw it and began to watch it very closely. Within 4-5 days of being home it had turned completely black and we were told to take him to the Hamot Hospital In Erie, PA. They had to do surgery due to infection and due to how bad it was. He now has a giant hole in his hip/leg that will take years to heal. Please, help. We don't want this to happen to someone else and we feel he deserves something out of this whole horrible ordeal!