≥In what way is an anti-parasitic drug supposed to help a viral lung infection?

While I have no interest in making a case for ivermectin and covid, you might be interested in the vast, highly relevant field of repurposed drugs. A fair example might be salicylanilides, eg niclosamide - a drug pretty exclusively used for a particular tapeworm, but being repurposed for incurable gonorrhea, c-dif, h-pylori and other conditions.

*Edited for shitpad typos