Can't cope with undiagnosed abusive sister

[Cailin2019]

My undiagnosed BPD sister developed a physical illness at the end of October, but has gone completely mentally off the wall with it and believes that she must have a fatal illness. I was there for her for months with constantly phoning her and visiting her. But the stress of dealing with someone who is delusional got too much for me and it made me very sick. At Christmas my husband told her to leave the house as she was freaking out. The next day she sent me a whole host of abusive messages.

So I didn't speak to her for a week or so aside from sporadic texts. Then she apologised and said she couldn't believe she had sent the texts but that it was from mixing her meds with alochol. I have been LC with her since and told her I can no longer take calls before work or at work and that I don't like calls anyway (this is very true).

Anyhow she was supposed to go down the country for the next few days while her husband was away, but refused to go. I missed a call from her at work and when I texted her she wanted to stay with me*. When I said she couldn't she started with the abuse again. Everything from how her friends can't believe how terrible I am, to belittling the debilitating illness I live with, to stuff about how our mama and her sister were super close, and then stuff about how my husband is so great and how he has given me everything. She then asked how would I cope if he died. I ignored it all, but am soo upset now.

She needs to be hospitalised but refuses to do so. Her doctor actually said she could be sectionable, but her husband doesn't want to do that. And she seems to have developed a drinking problem too.

I feel sick to my stomach and so scared too.

*It is so stressful to have the same conversation over and over, and she does things like talk loudly on the phone early in the morning waking me up. Plus, she follows me around when i am getting ready for work and doesn't even get that like most folks I don't have time to chat before work. Furthermore, my husband works from home anyway and he doesn't want her in this house.

[Isanni]

I'm so sorry you have to deal with this. I hear you are struggling with wanting to be a good sister and sense you feel sad for her and you also want to be a good wife and good to yourself.
Boundaries are not bad. You married someone and he should be your focus. Especially if he is a good guy.
Regardless of the illness, the one with it has to own it and is the only one who can heal from it. Until then, there is little you can do but to protect you and your family. At the same time, there are good communication strategies to learn to better communicate with your sister if you choose to. Validating, stating boundaries, being clear on what you will/won't do, reflecting back what you hear from her, etc.
I sense you are pained by not giving in to her. That means you have a caring heart. However, if you set boundaries such as she not living with you, keep your husband/kids as the priority, and learn to listen and validate your sister and perhaps suggest outlets and therapeutic avenues for her, you might feel better and nudge her.
It's a very difficult position to be in. As a mother of two girls, one diagnosed with borderline traits, I would want my non borderline kid to set and keep boundaries in place for the benefit of both kids.

[Cailin2019]

Hi,

The issue is she hates boundaries. To her it is a terrible insult that I won't let her stay at my house or talk to her by phone. And it upsets me that she says her friends are shocked I am not there for her. Thing is I was for 2 months until she attacked me verbally with the nastiest of messages - not once but twice. Plus, she lies so much that it is hard to know if her friends are even saying that. It is very upsetting to me though as I have done so much for her.

She is so bad that nobody can handle her anymore and her husband is a broken man. So she is going to have to be hospitalised, but I am not sure when that will be. 

She knows all about BPD and its associated stigma. He best friend is a psychologist whose brother has it, so she doesn't want the diagnosis. Plus she has never self harmed or had any addiction (though recently she seems to have developed a drinking problem), so her BPD is less obvious.

Since diagnosis is by clinical interview if one knows the symptoms it is super easy to lie and avoid the diagnosis. And last time she was in hospital she was under the same psychiatrist who diagnosed her with severe anxiety and fell for her "pretty woman with good job and an inability to hide her real self in public" act. So how will she ever get diagnosed?