the short answer
Alcohol and fat loss can coexist. Alcohol carries about 7 calories per gram, briefly lowers fat burning, raises appetite, and disrupts sleep - all of which make a deficit harder to hold, though none of it blocks fat loss by itself. As long as the calories fit the deficit, a client can still drink occasionally and lose fat.
This article is general nutrition information for coaches, not medical advice. Dependency, health conditions, and interactions between alcohol and any medication are clinical questions - refer those to a doctor or registered dietitian.