Mainstream doctors spend years studying about the human body, all that can go wrong with it and how to manage them. There is no substitute for this until AI and IoT become mainstream.
'Googling' to get a diagnosis and treatment will result in information overload and unnecessary anxiety.
Next Steps
Stop listening to her. It will only encourage her. Don't make fun of her though.
Health Tips
Get your friend to see a good, patient counselor. Needs to understand why what she is doing is harmful to herself and to others.