From Celebrity's site:
https://www.celebritycruises.com/faqs/beverage-packages
My travel partner is pregnant/recovering alcoholic/medical issue that does not allow them to drink, do I have to purchase for them?
Our policy requires that any guest wishing to purchase the Drink Package must do so for all other guests of legal drinking age in the same stateroom. However, we will make an exception for the following:
Exceptions:
Children 12 years old and under: will NOT be required to purchase a Zero drink package.
Teens – A Zero Proof drink package will be added
13 -17 years old (Europe, Asia, Australia)
13 - 20 years old (USA)
Pregnant guests – A Zero Proof drink package will be added.
Recovering alcoholic or medical issue that does not allow guests to consume alcohol. – A Zero Proof drink package will be added.