I think she drinks because even at 60 years of age, she still doesn’t know who she really is. She projects a person she wishes she was to other people, but that person isn’t her, and as a result she is never comfortable in her own skin. So she numbs that negative affect with drinking.

It’s easy to expose by just trying to have a real conversation with her. Ask her how something makes her feel. What she likes to do, etc. you will see the simulation for what it is.