Naltrexone works by reducing cravings and the pleasurable effects of alcohol. All the person has to do is take a pill daily. The person doesn't need to change any other behaviors or quit cold turkey. It just makes people want alcohol less.

The person doesn't need to be a total train wreck to get help. It has been prescribed for "hazardous drinking", which affects about 670,000 of us. Talk to your GP for more info.

https://www.medsafe.govt.nz/profs/datasheet/n/naltrexonetab.pdf