It's beginning to look a lot like a regular chaotic Christmas

So almost a year ago my mother kicked off in spectacular fashion.  Inventing illness and drama and putting more and more demands on my sisters and I.  It all culminated with twin and I ending contact with mum.  So now we have gone almost a year without contact but the trouble never ends.
When I got home from work last night there was a phone call from the community rehabilitation team in our area looking to confirm our details because they have had a referral about mum.  I tried to phone back but the number I had was wrong and the switchboard had closed for the night.
Oh god I thought its all starting again, but before I settled into full blown panic twin called big sis.  Turns out that mum has started all the things she did last year with big sis.  Mum has a static caravan up were Big Sis lives but has been turfed out for the winter so had to return here.  She was also supposed to have Nanny staying with her.  As soon as she was turfed out she was in constant contact with big sis.  Starting with the usual that she is ill, that Big Sis doesn't do enough for her, that her illness was all our fault, that we are evil daughters.  Then she ramped it up by calling ambulances out in the middle of the night, saying that she had a stroke or some other imagined illness.  Then she would phone Big Sis to tell her.
In the end Big Sis insisted that Nanny went home, as if mum is ill she can't look after her, then mum managed to get herself admitted to hospital and ramped it up even more, look I am really ill you need to do more for me.  Then she did all the things that she did last year to Twin and I to Big Sis.  In the end Big Sis snapped and told her she wasn't taking any more of her nonsense so now she has reduced contact with the other mother too. She hasn't gone completely non contact and is still receiving lengthy texts from her but now she understands what we have gone through.
Big Sis had a year of being mums only contact and has realised how selfish and narcissistic she is.  She even apologised to Twin as she hadn't realised how bad mum could get.
Part of me is elated that Big Sis now realises how bad mum is but the other bit is scared because now mum is back here and back in her flat (Twin checked) and is probably gearing up to ruin Christmas for as many people as possible. She has probably told the community rehab team that her darling daughters will look after her and I am now faced with telling them the truth.