There are some mental illnesses that look a lot like alcoholism but are biologically based. Narcissistic Personality Disorder is one of them.
That being said, it sounds like your mom found peace with her decision finally, and is walking on sunshine about it (reality will set in later, most likely). I'm guessing her correcting you was part of her own processing, and had very little to do with you.
Here's hoping this change makes life easier for you, and not more complicated.