Do my fiancee have a case for compensation?

My fiancee had lung surgery to remove bloodclots, was successful. Four days later, the day of discharge. He suffered from an Cardiac Arrest. While transferring him to surgery, he was without oxygen for 10 minutes and now has "Short& Long Term Memory Loss". He also recieved a trachea and a nurse suction him too far and damaged his bronchial tube. He was given too much antibiotics which caused "C Diff". Does he have a case? I filed Grivance against the hospital already. Now I was told after their investigation. I could appeal ..but I want compensation for his injuries.