In the movie If I Stay, Mia got in car accident with her family. Her parents died. Her younger brother died in hospital. Mia was in a coma. We saw her consciousness (maybe, I'm confused) going through stages of her life. She was deciding if she should stay alive or not. At the film's end, we learn she decides to stay.

My problem is determining how she knew that her family was dead. She was in a coma. I'm guessing somehow she heard after the accident that her mom died immediately. But how did she come to know that her father and brother died? There is no indication in the movie that news of her brother's death was shared beside her. So there is no way that she knew about her brother. So was that Mia's ghost that was exploring in the hospital and heard these news? Or is that her soul or her consciousness and that's how she came to know about those deaths?

What did the writer mean? Did I miss something?