Talk to Gastroenterologist on Gastrointestinal Problems

Assalmualikum! I have a question regarding an obese 46 years old male who's been having gastrointestinal problems for a few days. He has a mild fever and moderate pain in the upper stomach. He is also complaining about sulfur burps. His fever is not constant, but it keeps coming back after every 4-8 days. Additionally, he got his gall bladder removed five years ago. All these symptoms are quite concerning, and that's why he will visit a gastroenterologist soon. In the meanwhile, can he do something to improve his condition? God forbid, can it be something serious, or is it just Bacterial gastroenteritis?