Named changed for this as very sensitive.
My half DSis (same Dad) has had a chaotic life. She’s 13 years older than me. Dad split from her mum when she was 2 as she cheated and was unstable (turns out 30 years later she is bi polar). My sis didn’t have a very nice childhood from what I can gather. She saw Dad every other weekend - but less as my brother and I came along (which I think is awful )
There is a massive backstory that would fill pages if I went into it. So I’m sorry if anything comes up that seems like a drip feed later.
Important points;
She’s was sexual abused by her step dad at 18. Her Mum blackmailed the Step dad into signing over the house rather than go to the police.
She’s never been able to hold down a job for long.
Married a man from Barbados after repeated holidays there (back when you could get cheap deals in the late 90s early 2000)
He’s still there as she doesn’t earn enough to qualify for visa to bring him over
She’s always drunk loads and had a party life style. Not helped by always working in bars
Always expected her parents to bail her out with money (they must have spent thousands over the years) never been able to budget or save
Always run away from a situation that got a little difficult and always blamed everyone else for her situation. (Shes has 25 years of bosses bulling her across hundreds of different jobs 
Anyway like I said loads more too it. But she has finally burnt her bridges with her mum after drinking all her Christmas wine while she was away and found unconscious on garage floor. So her mum chucked her out (100th time I’ve the last 25 years) and said she can’t go back.
She admitted to dad she has a problem and wants help. So he took her in and said he would pay for counselling on the condition she does not drink and goes to AA. She went to one meeting and refused to go again. She then back tracked and said she didn’t have a problem. She kept drinking in secret and was being argumentative when drunk and collapsing on the floor. Hidden bottle of gin under sofa cushions. Getting blind drink in 45 minutes from leaving counsellor and arriving home. Dad said that she has one more chance to try and stop, go to GP and get help etc and she said she’s leaving as it’s not working out and she can’t be herself (I.e not drink)
So now she’s gone to a friends up north who has two youngish kids and I just can’t see it lasting. She has no job or money- does she expect this woman to fund her? How will this woman feel when she wets the bed as she is so wasted (as she has done multiple times). I can just see it ending in disaster.
Dad said he won’t have her back, their relationship has broken down as has the one with her mum. I have two preschool children and a small house. I can’t have her here and expose my children to her behaviour. Especially when she won’t admit she’s a problem or seek help.
She has suffered in her life but she has used this as an excuse for her behaviour all these years. Surely there is a point where people have to own up to their own behaviour? She’s never sought counselling over the sexual assault despite people encouraging her so many times. The only reason she went this time is Dad said she couldn’t stay otherwise.
People have helped her again and again and she just defaults to her same behaviour and nothing changes.
What can I do to help her. People are giving up on her and I have visions of her ending up in the street and drinking herself to death.