|Maybe it is GERD? If she's had it for a long time, her esophagus could be very well be deteriorated a lot... in which case, it's not going to be hard for the food to come right back up. I've gotten food coming back up sometimes because of GERD.
To avoid this happening, if this is her problem, she needs something like Nexium or the "purple pill" to keep the reflux at bad and also REPAIR the damage to the esophagus, which other medications don't do. She should stay away from acidic foods and only eat very small and frequent meals rather than the traditional three meals a day.
I hope that helps out a little.