I am so sad.
Backstory is I left ExH years ago when kids were small as he' always been cold and distant and was starting extreme anger towards me. I got away before he hurt me physically we stayed with my parents and got a new life!
ExH remarried and had kids every weekend and all settled down, he said he couldn't afford what the CSA took from him (about £400 per month, I said ok just give what you can - he gave £100 per month and money was tight but i built a business and we managed!)
When the kids were pre-teens he decided to live in France and that was that - he went over with his wife taking my kids' half sister, who they adored. he stopped the £100 payments. I met my DH and we all moved on.
When my DD hit the age of around 14 she started to show symptoms of MH issues and, long story short, after the deaths of both my parents who adored the kids she had a massive mental health breakdown aged 17 and has been in and out of hospital since, she is able to live independently a lot of the time and we all need her to as she has extreme anger issues and can get violent with this, when she is triggered, which can be by something as small me scratching my face, she is a monster. That is not my girl that is the illness, when she is not angry it is very sad and she knows she misses out on life, she never held down college or a job or kept friends for long - its heartbreaking she longs to start again with these things but can never keep it up because she struggles too much. She was diagnosed with extreme BPD and psychosis years ago she hears violent voices in her head. She is now 23 years old.
Recently, just before xmas she had a breakdown, I tried to look after her and things got very nasty and frightening, I can't talk about it as it traumatises me but my life was in danger and so was my dd's she tried to run under a car once, i was unable to sleep and it went on for four days and nights, the healthcare services would not help us until our social worker took it to the top and made someone accountable if one of us were hurt or killed (he saved us, or it would have carried on and someone would have been hurt) and then she was admitted to hospital for a couple of months.
She's been in and out but although I speak with her several times a day, unless she doesn't want me to of course then I have to wait and worry until she does, but although I speak on the phone to her, I will not have her with me alone and will not have her stay at our home again.
She has begged me to rescue her from the flat as she thinks the voices are real people going to attack her but I can't as i am suffering from post traumatic stress disorder since the previous time she came. I've had advice to let her get help from healthcare services now as they have really started to put in some real support after what has happened and they spend a few hours a day with her. I am taking advice all the time on how to handle this and learning to put in strong boundaries as i've been told it is her only hope of recovery, I have also been told if i let her back to my house services will stop taking it seriously and leave me to it again. I know this to be true, every time they think i can cope they leave us to it and just offer skeleton care.
Throughout the year's my ExH stayed in France - he knows but only texts her on occasion! He has two sisters who claim to love dd and she has four cousins including one who is 20 and i have had a couple of phone conversations with explaining the illness and she promised to help, she had dd over for a couple of days when her mum was on holiday. They are all as flakey as hell though and they either break promises to visit or stay away. i have been defending them and making excuses up to HC Professionals for their lack of involvement as dd can be so difficult.
Anyway there we were at rock bottom dd begging for help me phoning her every hour and her saying she was going to die so out of desperation I suggested she call her father's family and get them to pull their weight a bit, I didn't put it like that to her of course but dd said on the few occasions she has seen them she feels like a burden, I told her they said they loved her and i believed them and we are desperate for help now so nothing to lose, so she did.
Next thing she tells me its all ok other family are looking after her - i thought "wow wonders will never cease' they actually did it! She was texting me telling me one sister was having her until she was rehoused into supported accomodation or something and that she was being well looked after. I couldn't believe it!
Then the cousin inboxed me on fb saying her auntie had dd and asking for my number - I thought we would have abig chat and organise how we were all going to support one another so i happily told her 'yes i know she's with (auntie) we couldnt have her because i still suffer from post traumatic stress from the violence before xmas and my number is *'
Next thing I know I am receiving several of the most crude abusive texts from the other sister (not the one with dd) saying I am a disgrace she would never leave her dd and palm her off to other people do I not realise people have been off work for this what a burden i should be ashamed, call myself a mother, I am pathetic with my 'post traumatic stress' and I should learn to look after my own dd and not involve them as we are doing 'YOUR JOB' this is all in crude aggressive language - think Jeremy Kyle! The cousin joined in the attacks!
So now my dd is back in hospital which 'really put them out getting her admitted' apparently (yes I know, I do it all the time on my own apart from dh and sometimes my son who's 20 does it!) Apparently the cousin went through hell because i palmed dd off on her for a couple of days last year and in 2010 when (the sister texting me) had her it was 'disgaceful' that they 'keep having to do YOUR JOB for you'
Sorry this is long - if your still reading thanks, the situation is the other sister (not the mad one) is going to have dd to stay, when i saw dd in hospital she was so happy her family want her and she said it calms her, she was even talking about seeing her dad in France (she would have to travel to him of course he won't come to her).
My heart is BROKEN she is so happy but only I know - they don't WANT her at all! What can I do??
I just needed to get this out sorry there's not a lot I can do i've tried to communicate saying we've had a misunderstanding lets talk about going forward - nothing! They don't want her and begrudge her but dd is SO happy! 
I anyone can help? I'm so upset!