The problem with this is that in these people's minds, if <insert whatever magical cure to covid they know works> doesn't work, it's always some other factor than the cure itself that is causing it to not work. It doesn't prove to these people that those things don't actually work.
If the hospital administers the 10,000mg of Vitamin C, which won't work (according to what we know from medical experts), when the patient dies his family would just claim that the hospital didn't give him the right dosage, or they should've administered the vitamin C earlier, or the hospital claims that they administered the vitamin C but really didn't administer anythiung, or what they administered was not the right vitamin C / was not vitamin C at all. It doesn't cross these people's minds that maybe vitamin C doesn't work. Swap vitamin C with hydroxychloroquine or ivermectin or whatever other covid cure flavour of the month it currently is.