I am an adult with a sister with Down's Syndrome who is 3 years younger than me (also an adult). She still lives at home with my mum and mum's partner, whilst I live a couple of hours away. I am finding it really difficult mentally whenever I come home to visit now due to tensions in the house over my sister's behaviour. She takes money, hides food and alcohol, and just generally doesn't do as she's told by them and basically rules the roost. I know my Dad and Stepmum also find it really tricky, but mum doesn't involve them in any decisions to do with sisters care and sister doesn't spend weekends there anymore because she says she doesn't want to (my suspicion is because she can't do what she wants when there as she does at mums).
I'm really close to my sister, and did a lot of care for her when we were kids due to my mum's own mental health struggles. I'm also close to my mum in our own way, but I don't know if she fully understands how much of a parental role I played in my sister's life when I was a child myself.
Myself, my dad and Stepmum all think that the only way my sister's behaviour will change is for her to be in supported living. She needs a full reset and change of routine, boundaries, new experiences etc. My mum find's this really difficult to process, I know she knows it's the right thing but she isn't moving on the process.
It's got to a point where I don't want to come home and visit because of the atmosphere. Mum's partner is fed up with my sister and her behaviour, and fed up with my mum's lack of action, but he also doesn't have much understanding towards her disability. Today whilst at my mum's, my sister confiding in me that she was kicked out of a local shop for stealing. I don't know whether to tell any of the 4 parental figures in her life because I just don't know what will be done to help
I want to find a way of supporting myself to cope, but also how to start some sort of mediation between everyone involved about what's best for my sister, or maybe tips on how to broach difficult conversations about someone's duty of care/future provision? I know it shouldn't be on me as the sibling but I feel powerless at the moment and not sure how to change things.