A possible side effect of the malaria drug cocktail to treat the virus is heart problems mostly from the antibiotic azithromycin. He discovered substituting doxycycline still works in combination with hydroxychloriquine. Worked in 38/47 patients including an 87 year old women with hypertension an underlying condition that contributes to the fatalness of the virus. 2/9 died. Dr admits it's not a full fledged study with a control group etc.
https://nypost.com/2020/04/04/long-island-doctor-tries-new-hydroxychloroquine-for-covid-19-patients/
https://nypost.com/2020/04/04/long-island-doctor-tries-new-hydroxychloroquine-for-covid-19-patients/