What Causes Vomiting Of Blood And Sudden Episodes Of Fainting?

Hello, I have a question about my grandmother. She is 68 years and had a car accident 2 weeks ago. She flew out of the front window and after 10 meters she hit the ground. The doctors did some scans and examined her. Everything was fine except for 2 broken ribs. She was able to go for walks outside and was not confused at all. But now after 2 weeks she suddenly feels not so good. She says :her belly feels like it s filed with water and she fainted sudenly. After she woke up she started vomiting a lot of blood. +- 2 liters. She is in the hospital and says that she feels fine again, the doctors can not find the reason of all this. What can this be ?