The medical establishment has had a long-time problem with arrogance and attacking people with vision:
https://en.wikipedia.org/wiki/Ignaz_Semmelweis
The medical community in general is very good at scoffing at anything that doesn’t come from THEM. They stick their noses up when it comes to more natural ways.
If this doctor has been administering Vit. C to people with sepsis and watching them become well, that’s all the “proof” I would need.