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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

To finally cut my sister out my life?

55 replies

TakeSomeBlame · 16/01/2026 13:28

I have always had a tumultuous relationship with my sister. She is diagnosed with depression, anxiety, borderline personality disorder, and more recently, autism and ADHD.

She has always been extremely unpredictable and her emotional regulation is non-existent. She can go from 0-100 in an instant. This has lead to her having very poor relationships throughout her life and finding herself in trouble with the police and social services at times (e.g. she has destroyed property belonging to other people and trashed the house, leading to concerned neighbours reporting her). She spends a lot of time in bed.

The most difficult trait to deal with is her persecution complex. She believes that everyone else is wrong, even in the face of overwhelming evidence. This means I am constantly treading on eggshells. She only has me, our mum and her husband in her life. We all have to agree with what she says and does. She says that everyone in her life has abused her. Our late father, all of her exes, her friends (who one-by-one have had nothing to do with her) are all apparent abusers. She has not been in employment for many years because employers cannot cope with her. Therapy doesn’t work as she is manipulative and deceptive, she either doesn’t tell the truth, or, once they cotton on and suggest she may be the issue, she will decide the therapist is crap or isn’t ’trauma informed.’

The latest situation is she has cut off her teenage son. She began to bombard him with messages about his dad, accusing him of all sorts of horrendous abuse. Her son, my nephew, who has had to see this unfold many times over the years, does not believe her and she has now decided her son is also abusive for not believing what she is saying about his dad. She has also made it clear to me and my mum that we are also to have little to do with our nephew, and if we were to have a relationship with him, she would see this as a huge disloyalty and that we are not believing her about her trauma and abuse suffered at the hands of her ex.

AIBU to finally cut her off? We’re both in our late 40s.

OP posts:
JoshLymanSwagger · 16/01/2026 13:50

Your nephew needs you more than your sister.
💐

LindorDoubleChoc · 16/01/2026 13:40

Have you diacussed this latest drama with your mother? It does sound ike the last straw. Please reassure your nephew that you are there for him

TangerinePlate · 16/01/2026 13:36

Your poor nephew.
Like hell I would cut him off to go along your sister demands.Your relationship with him is not her business.

TakeSomeBlame · 16/01/2026 13:36

MatildaTheCat · 16/01/2026 13:32

She sounds a nightmare but if you cut her off will this place more burden on your mum? I think I’d do more of a very low contact and grey rock rather than cutting her right out. That will just give her additional drama and persecution to ruminate on.

I’d like to maintain a relationship with my nephew but if she finds out about this, she will cut me off anyway and I’ll likely become one of her many abusers. I am concerned that this could affect my life. In the past she has posted on social media about her alleged abusers and she has also made police reports, luckily they haven’t come to anything.

OP posts:
MatildaTheCat · 16/01/2026 13:32

She sounds a nightmare but if you cut her off will this place more burden on your mum? I think I’d do more of a very low contact and grey rock rather than cutting her right out. That will just give her additional drama and persecution to ruminate on.