Well, the quack actually did publish a preprint of his alleged 99.3% survival rate, and it is based on an analysis of 141 patients.
Yes, he claims he had a subject size of 372 patients, of whom only 164 were given his cocktail, and his analysis refers to 141 of them (median age 58 years, IQR 40-67; 73% male). There is no report of the outcome of the other 23 patients who got the cocktails, which raises a large suspicion that he omitted them because their results were worse.
He is claiming his numbers are far better than a similar demographic of patients who did not receive the HCQ cocktail, however not an ounce of information is provided about these control patients.
Furthermore, I don't believe he discloses if his 141 treatment group also took other medicined like steroids we know help.
Prima facie it appears he cherry-picked a medium risk group whose mortality rate echos the general population rate. His patients are all under 80 with some risk, whereas the general population includes 20yo + 90yo.
https://www.preprints.org/manuscript/202007.0025/v1