Trump doesn’t need to fire him, he just needs to listen carefully to Fauci’s advice, and then do what works, regardless of what Fauci says. The Press will howl, as always, and then be temporarily chastened when Trump turns out to be right, as is usual. The people will be served, and people with open minds will be swayed.
From here, it looks like he got those promising drugs distributed in spite of Fauci and other Left-endorsed gurus, not because of him.