I'm not an expert in this area and I haven't studied the particular issue with HDVY. But at the time warrants were issued, I would think the authorized shares would have to be high enough to accommodate the warrants when they are exercised. Otherwise, as you suggest, there would be a major problem if O/S exceeded A/S.
With the markets tanking last week and HDVY fighting a legal challenge, I was encouraged that the stock price closed higher on Friday. Of course that doesn't mean it will continue higher in the upcoming week. We'll see soon enough.