Welcome to the BPD crew, although under my local health authority it's called EUPD as they don't like the use of the word 'borderline'
. She unequivocally does not have BPD/EUPD, nor does she have Bi-polar disorder. I agree with you entirely that she has no empathy, her mania is drug (chemically) induced not emotionally related. Bi-polar doesn't on a needle point switch either, mania is day to day, week to week - NOT minute to minute!
I similarly hate how people think that by labelling her as mental health issue it's OK to behave the way she does. It's not, she is unstable from drug and alcohol misuse - that is the underlying issue and until it's resolved then a psychiatrist/psychologist won't get involved.