UV light can in theory be used against infections in the blood (and I think has in the past, but who knows how well it worked, probably poorly), and intravenous

UV light can in theory be used against infections in the blood (and I think has in the past, but who knows how well it worked, probably poorly), and intravenous monoclonal antibody injections do bind to viruses and help them to be "cleaned out" from the lungs. It is known to work in the case of COVID-19, see Evusheld currently, and older monoclonals that worked against earlier variants. It's possible he was talking more along the lines of hydroxycloroquine, a clear candidate for the treatment of SARS-like viruses (the virus that causes COVID-19 is SARS-like), but it's now thought that was a mistake on the part of the researchers who applied it to SARS, testing in the wrong tissue type (not lung cells like it needs to be tested in). It's likely most of Trump's suggested treatments would not really work in practice though either, as by the time you get to the hospital it's almost always way too late for any sort of anti-viral treatment, unless you are in the hospital for some other reason or gastrointestinal distress/a digestive problem caused by COVID-19. If you look at how well early IV remdesivier has been operationalized, I doubt most people would want to be confined to a hospital bed for hours with lights and HCQ injected into their bloodstream while they still feel like they just have a cold, no matter what the COVID-19 test says.