Hey Atreyu!
I cant say everybody in my family had enough. I decided to set boundaries and go NC, cause I couldnt take relatives behaving like that anymore. The reaction was painting me black, silent treatment and rude remarks indirectly sent to me. Meanwhile, others are the golden ones and they really enjoy being portrayed like that, so they created a close bond.
I see more hope in your case, cause everybody has realized the problem and are behaving accordingly. Maybe your mom will realize she needs help and finally go for it. Maybe she will resent the boundaries at first and "fight back".
I suggest you read more abt BPDs, theres great material in this site and helped me understand and deal better with the situation. Good luck to u.