Disneydiva113011

We have a family cruise booked for December with my parents and siblings, it’s all booked and paid for but my partner now is very unlikely to get the time off work due to a new job. We are both happy that I still go if he isn’t able to but don’t know if we need to notify them or if he can just not turn up! Any advice - I’m not expecting refund if he can’t travel, just don’t want it to cause any issues on the day.