Fractured Ankle & Surgery. On her own?

My mother broke her ankle by slipping in bathroom two weeks ago. We went to the doctor and he took an x-ray. He said that the ankle is broken and will require surgery by inserting screw and plate. My mother can put pressure on her ankle, she can walk, move her toe fingers, go to the bathroom , go up and down on stairs on her own and even pain seems to be minimum sometimes. Her foot is swollen and there is a little swelling on ankle along with few others blue bruising. 18 years ago, she broke the same ankle and got plastered for a month and a half along with 6 months of problem. She doesn’t want to do the surgery because she is scared that she will get more complications after surgery than she is facing right now. I honestly don’t know what to do. Can her ankle be fractured from 18 years and she walked on it normally? What happens if she doesn’t do the surgery? Can her ankle heal on her own? Please help me.