Our expert says:
Hmm. Her mother apparetly has a complex set of medical problems, further complicated by her alcohol and drug abuse and her refusal to properly seek help or follow proper advice. And an abusive father --- an unattractive and undeserving couple, who she probably still loves, even if somewhat illogically.
Your fiancee surely deserves some properly expert counselling / therapy from a shrink or professional counsellor, to sort out the unhelpful lessons learned in the years of being abused, to enhance her self-esteem and confidence, for instance. This would be in addition to talking with you, not to replace your important role here.
It can be very difficult to help someone you love, in part because it is so hard to be neutral when this is needed. A therapist, espeially of the CBT variety, can help her to "un-programme" herself.
As to your specific questions -- (1) there's no useful way to force her mother or father to get the treatment they need. Theoretically if a person is a danger to themselves or tohers because of their mental state there could be a mechanism for requiring compulsory treatment --- but this doesn't apply to bloody-mindedness, stubbornness, and other annoying habits which are not due to identificiable disease. And the sort of treatment they need, only works with their full co-operation, which cannot be compelled.
As for (2) We can't for various good reasons recommend specific shrinks, but FAMSA could do so, and the variety I would strongly recommend would be, if available, someone practising Cognitive-Behaviour Therapy, CNT, for which there is the best evidence from goo research of effectiveness.
The information provided does not constitute a diagnosis of your condition. You should consult a medical practitioner or other appropriate health care professional for a physical exmanication, diagnosis and formal
advice. Health24 and the expert accept no responsibility or liability for any damage or personal harm you may suffer resulting from making use of this content.