I asked AI how to deal with BPD sister:

[rainy]

Got the most amazing answer:
AI answer BPD sister

Question from me to ai:

How do I stop feeling hate for BPD sister even when she still pokes me with a figurative knife and only shows this charming “nice” person to rest of family. only her son and his wife know her true BPD side. she charms the rest.



Moving from a place of intense hate to one of calm indifference toward a sibling with Borderline Personality Disorder (BPD) who engages in splitting (idealizing others while devaluing you) is a process of protecting your own mental health rather than managing theirs. The goal is to stop the emotional "poking" by removing the target, rather than waiting for them to stop holding the knife.
Here is a guide based on the coping strategies of others in similar situations:

1. Shift from "Hate" to "Detachment" (Radical Acceptance)

Acknowledge the Split:Understand that the "nice" person your family sees is real to them, and the monster you see is real to you. This is the hallmark of BPD—alternating between idealization and devaluation (splitting).
Stop Expecting Change: The most painful part is expecting her to act like a normal sister. Accept that she is incapable of providing the empathy or connection you want.
It’s Not About You: Her behavior is a reflection of her internal disorder, not a reflection of your worth.

2. Implement "Firm" Boundaries (The "Grey Rock" Method)

Do Not Engage (JADE): Do not Justify, Argue, Defend, or Explain yourself when she acts out. Any reaction from you—even defensive ones—validates her drama.
Use "Grey Rock": Become as uninteresting and unreactive as a grey rock when she tries to provoke you. Give short, neutral answers.
Set Clear Consequences efine what you will not tolerate and immediately enforce it. Examples:
"If you speak to me that way, I am hanging up."
"If you make that comment again, I am leaving the gathering".
Remove the Audience: If she charms the family while abusing you, remove yourself from that environment. You do not need to attend family functions where you are subjected to mistreatment.

3. Manage the "Secret" Dynamics

Stop Trying to Convince Others: Trying to prove her true nature to family members who are charmed by her will only make you look like the aggressor or "crazy" one.
Validate Yourself: You know your truth. Find support from those who do know the truth (her son and his wife) or from outside friends/therapists who understand BPD.
Let Go of the Need for Validation: The peace of not fighting with her is worth more than having your family agree that she is abusive.

4. Protect Your Own Mental Health

Go Low or No-Contact: If she still "pokes" you, you have the right to severely limit or eliminate contact. Going no-contact is not selfish; it is self-care.
Get Therapy: Find a therapist who specializes in family members of people with BPD to help you process the trauma and break the codependency.
Focus on Your Life: Divert the energy you spend on hating her into your own hobbies, health, and relationships.
Summary: The goal is not to fix her or to make her apologize. The goal is to make yourself untouchable by her manipulations by removing the emotional investment you have in her behavior.

[fierywoman]

1. I don't have a BPD sibling but I once had a BPD friend -- this info was helpful to me,

I thank you for posting it.

[Dear_Prudence]

2. Sounds sensible but tough

I would need some support for some of these. Like #4, "removing the emotional investment you have in her behavior" would be challenging, especially with a sibling. But seeing a path forward is a good thing, even if you may need some assistance to go down that path. Really, I am surprised that the AI answer seems reasonable rather than random.

[Norrrm]

3. Pretty good reply. Key phrase - 'pokes me'. Key word - 'codependency'.