Experimental drug holds promise for treating the coronavirus: https://t.co/gCDvENUt15 @rehemaellis reports now.

— NBC Nightly News with Lester Holt (@NBCNightlyNews) April 8, 2020

But questions remain about the quick recovery. Was it the drug that lead to the improvement? Or would the man have gotten better the next day anyway?

Susan Kane said remdesivir appeared to work quickly for her husband, too.

"On the very next day, he said: 'You know, I think it's lifting. I think I'm starting to feel better,'" she recalled.

Chris Kane is now home and, although he still gets winded easily, he is improving, according to his wife.

"We are 100,000 percent convinced that the remdesivir turned things around for him," Susan Kane said.

Because remdesivir is now officially in clinical trials at Providence Regional Medical Center, Kane's doctors declined an interview with NBC News, as they are unable to comment on the efficacy of the drug before results are made public.