As per the Symptoms and history you have mentioned that she had same problem few years back but it resolved own its own by time, it more likely GERD(or acidity in common term) ,
Next Steps
CAP RABLET D 1CAP p/o Empty stomach for 10 days in morning
TAB ESMOPRAZOLE 40mg p/o EMPTY STOMACH in evening for 10 days
Health Tips
Take tummy full meal
don't skip Breakfast, Lunch, and dinner
add meals in between breakfast and lunch, and lunch and dinner that makes 5 times meal in a day
avoid caffeine intake specially Empty stomach and not after Just water
if not avoidable take adequate food than consume caffeine (tea/coffee)
Try to reduce spicy and oily as much as possible