What wasn’t reasoned into her head, can’t be reasoned out.
Sounds like there’s a good chance that you may need to apply a method I use when dealing people who believe in conspiracy theories. It’s largely a psychological thing, and it has very little to do with proof, evidence, logic, reasoning and science. No amount of evidence is ever going to solve a problem that is psychological in nature. Religious cults and conspiracy groups share some characteristics, so maybe this is applicable in her case too.
The idea is that people believe in crazy BS because that makes them a member of a group. That gives them an identity and makes them feel like they’re a privileged group for knowing some “hidden truth” about something. It also produces an “us against them” dynamic between the in-group and the out-group. Many individuals in these groups also have sub-clinical psychosis, narcissism or paranoia accompanied by anxiety and loneliness. This setup means that they find these BS nonsense groups appealing, and that the misguided beliefs become essentially bullet proof. Fighting against these beliefs will only make them stronger.