The infrared light vests caused improvement in hypoxemia and blood clots. Probably through Melatonin.
Sunlight is believed to be very helpful (Freepers knew that).
But LED lights vests/belts etc are reasonably cheap and available at Amazon and Walmart. However the LED light does cause eye damage so be sure and wear protective goggles when using them.
The UV end of the spectrum kills viruses outright, and is more involved in producing vitamin D - but this is interesting.
The actual effect demonstrated on the MedCram videos is suppression of the TLR4 response. Breaking that chain reduces damage from related cytokines.