Depending on their status, there are options to stay in the U.S. beyond the expiration of their authorized period of stay, whether by filing something with USCI

Depending on their status, there are options to stay in the U.S. beyond the expiration of their authorized period of stay, whether by filing something with USCIS before their status expires (such as a change to or extension of visitor status) or by requesting "satisfactory departure" with CBP. There is also a chance that USCIS will relax or even waive expiration dates for a period of time but that hasn't happened yet.