Questions: Relationships

My girlfriend is an alcoholic, I have been with her for 5 years and living together for a year.

Her problems worsened around the time of the pandemic and her depression has worsened since then and she has become dependent on alcohol.

She will be fine when I leave for work in the morning but when I come home in the evening she will be semi conscious on the floor and there will be 2-3 empty bottles in the recycling.

Way back (approx 10-12 years ago?) her father cheated on her mother and broke up the family unit. Years later her mother is now back living with the father though they are NOT in a relationship.

We have had numerous interactions with medical professionals and one issue that keeps coming up is the break up of the family caused by her father's infidelity and lying she says "he broke my heart".

I have tried to involve her parents in her recovery by keeping them informed and have asked the father to engage in counselling with my girlfriend to try and get her past this. She had had counselling for this issue for the past decade but he never engaged with her on it and no-one in the family is allowed to talk about it.

Her father has now taken a very aggressive stance towards me since I raised the subject. He has asked me to leave his daughter and suggested she break up with me as I am a 'Toxic' person. My question is do I stay and fight it out to get her the closure I really believe she needs or do I leave which will mean at 35 she goes back to living with her mother and father? I'm at a loss to know as I love her but not the person the alcohol is making her become.