Does this constitute as medical malpractice. This could have been avoided with antibiotics that were supposed to be prescribed

My sister was admitted to the hospital to give birth to her son, she was in labor, her water had broke. After many hours in labor she had an emergency C-Section due to her sons heart beat during contractions. After her C-Section she was running a fever and had to stay in the hospital because of some sort of infection. She was on antibiotics thru an IV. She was told by her Physician and several RN nurses that she would be released and prescribed antibiotics due to her condition. Her doctor went on vacation before she was released and was not prescribed any antibiotics when she was released. She was home a day and a half when her stomach had swollen up on one side. She called the hospital and was told to just lay down. She decided to go to the emergency room instead. She was immediately admitted to the hospital and prepped for surgery by means of a blood transfusion, her C-Section had become severely infected and had reopened. They inserted a wound vac for her infection and has been in the hospital every since. She has been told that when she is released later this week a home health nurse has been assigned to care for her and she will still have the wound vac inserted for a while.