Thanks for your question on Health Care Magic.
I can understand your sister's situation and problem.
She is mostly having stress induced GERD (
gastroesophageal reflux disease).
It is due to laxity of gastroesophageal sphincter.
Because of this the acid of the stomach tends to come up in the
esophagus and cause the symptoms of nausea, vomiting, stomach pain, chest pressure etc.
First and foremost
stress management is required.
So better to
consult psychiatrist and get done counseling sessions. Try to identify stressor in her life and start working on its solution.
She may need anxiolytic drugs too.
For GERD, avoid hot and spicy food. Avoid junk food. Avoid large meals. Start
proton pump inhibitors and prokinetic drugs.
Don't worry, she will be alright with all these.
Hope I have solved your query. Wish you good health. Thanks.