Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.
Without the ability to examine your friend and obtain a history, I can not tell you what the exact cause of her symptoms is. However I will try to provide you with some useful information.
If your friend is unable to eat because of nausea or other symptoms, this could potentially be due to the
hydrocephalusHydrocephalus, in which case the
shuntCyanotic heart disease
Transjugular intrahepatic portosystemic shunt (tips) may not be functioning properly and may require revision. However, in someone who has a shunt and on examination and history there is no evidence of shunt problems, and if the hydrocephalus is under control, then a feeling of sickness with eating is not expected, and a search for other causes (gasteroenterologic, GI, causes) is necessary. Any food or liquids that contain sugar (that is broken down to glucose) is helpful in preventing or treating low blood sugar. But again, someone who can consume even small quantities of food on a regular basis should not have low blood sugar, so if glucose measurements in the blood are showing low values consistently, evaluation for the causes of this is recommended as well.
Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.