Hi Notoriousglo, No I don't think you're a pathological liar at all, there's clearly a lot of hurt you're feeling. So even if it didn't happen, along with the belief you've felt it happening
I can only assume your doubts are to do with whether one of your disorders is making you believe this when it's not true/the delusional idea, although sometimes with abuse people can just retain more "hazy", confused, doubtful memories or doubt things have happened.............sometimes as a form of protection against seeing what did happen.
If you're not absolutely sure something happened (or regardless!!) then maybe you could talk to a T or a pdoc about it???
I SO want to say yes from what you've said it happened to you (although it might hurt, at least validation???) but if you think maybe the disorders.............
But, I am sorry you felt that your brother wasn't supportive of you after you took such a big step in talking to him about it. That must have hurt a lot
And you know if the abuse did happen, which it might have (!!) there are still plenty of reasons why he might have behaved that way.........he might have tried to block out some of what happened, he might not want to admit what happened to you or them for fear of facing those feelings in himself or in you, he might have felt responsible for not doing anything (I know he wouldn't have been, but.......) and is denying it, he may have "normalised" it in his mind believing that if it happened then it probably wasn't that "bad", and some people who are abused do feel that their abusers must have been "right" in whatever they did/that they still deserve respect just because............we know differently of course but............
So maybe start with your T or pdoc, if you think you need to, talk to your brother again..........although I don't know if he would say much straight away if something happened, and if you still need help please contact a helpline because your feelings are real/the pain is real.
And of course if you want to talk more here..........

Alison