Need Resources for Navigating an Adult Sibling Relationship with Undiagnosed BPD

[Intotheforest]

Hi. This is my first post. I am just realizing through a great deal of personal therapeutic work that I have been raised in a family likely affected by undiagnosed BPD - or at least a combination of Cluster B characteristics. My family system has developed in ways that have normalized and enabled my sibling's behavior. Not realizing what I was dealing with, I tried desperately to get some help for my sibling but he surrounded himself with people that enable him - including my family system and his spouse/children. I watched chaotic event after chaotic event and illogical explanations that should have been questioned but were accepted - and a resulting downward spiral for him and his family. I finally pulled myself out of that system, and have continued to watch the behavior and its consequences worsen.  I've continued to try to call it out for my sibling and his family's own good with no success and have ended up feeling incredibly isolated from my family in many ways - and often this is directly tied to my sibling's behavior and characterization of me. It is apparent to me that this is part and parcel with living with this disorder in the family. Now my adult BPD sibling is in yet another crisis and has decided that I am an adversary because I dared to consider how his situation might impact me. My last conversation with him the extent of his illness was on full display and was, honestly, shocking. And incredibly sad. I don't believe that our relationship can be salvaged - I would be open to it if he would get help but cannot continue to try under these circumstances. Him getting help is unlikely because he does not believe there is anything unusual about his behavior and no one in his immediate circle will dare confront the behavior or challenge it in any way. When they do, he cuts them out (like me). So I don't have much hope. I would like to make better sense of these experiences and honestly, feel less alone and less exhausted by this. What recommendations would you all have for me to learn more and find some validation for these experiences?