Does she have one main doctor, who is in charge of seeing to it that all those medications she takes do not conflict with each other?
I would not be sure of any such thing. It's amazing how many prescriptions my dad was taking, and what a flake his doctor was about understanding drug interactions. Has your mom had an abdominal MRI? Does her regular doctor know she is going to the ER so often? It just sounds like she might need one doctor to be managing things a lot more firmly.
The other two possibilities, which seem less likely but worth mentioning, are that she is eating something poisonous, or that she is acting. You know the situation better than I do, but the concept that the pain is worse around the navel is puzzling. Unless she has an actual infection of the navel, that is kind of an odd place to have such severe pain that you need to go to the ER.
I read your post and sorry to hear about your mom. I think, you should visit the doctor, who has specialization in the same field and can better understand the real cause of pain.
Has she been checked for h. Pylori? Here is a link that may be helpful - https://www.mayoclinic.org/diseases-conditions/h-pylori/symptoms-causes/syc-20356171.
I hope she gets answers and relief soon.
Updates.. she have done 2 final tests today: barium swallow and capsule endoscopy. Both shows no sign of infections or problems. Her white blood cells are normal. She still in pain and they preferred her to surgeon. I'm not sure at her age can handle any surgery. She's getting weaker going through 2+ months of pain cant eat much and walk much. I really need more suggestions if any one have more info. It's surprised me that no Dr. and scans can detect it. :(
Is she better when she is in the hospital? I can't keep from wondering if she is ingesting something (at home) that is poisoning her or causing a medication interaction that has the same result.