I couldn't find HAL's information about what Covid treatments are available on board, but if you look at some of the other cruise lines, you'll see language like the passage below from Princess. Reading between the lines, if they're carrying ventilators (I assume so from the statement, "equipment and procedures... across the full clinical spectrum including intensive care."), they're probably carrying Paxlovid, IMHO.
Every ship has dedicated medical staff (doctors, nurses, etc.) operating ship medical centers to serve guests and crew on board.
They are up to date on the latest COVID-19 scientific status and trained on all relevant COVID-19 procedures.
We’ve enhanced our shipboard medical capabilities with the necessary staffing, medications, supplies, oxygen, equipment and procedures to triage and treat multiple COVID-19 cases across the full clinical spectrum including intensive care.
We’ve also expanded onboard medical roles to include staff responsible for overseeing public health issues, including outbreak prevention and response.
The medical staff requirements and equipment on each ship meet or exceed the guidelines from the American College of Emergency Physicians (ACEP) Healthcare Guidelines for Cruise Ship Medical Facilities.