The paper itself says that blood thinners are already recommended for Covid patients.

"In response to a number of reports that anticoagulant therapy with heparin leads to better prognosis in COVID-19 patients, both domestic and international organizations have issued clinical practice guidelines recommending that all hospitalized COVID-19 patients should receive thromboprophylaxis (mainly heparin treatment) even without clear symptoms of thrombotic complications and understanding their efficacy."