Honestly from your description, it sounds like you mother has a personality disorder as well, which would make sense with your brother’s diagnosis. People with PD are toxic and if you want to do what is best for yourself and your children, it’s probably best that you just not have contact with them. I know it can be difficult when it’s your mother and your close family, but you and your children will not be served well by attempting to have relationships with people who aren’t capable of them.
Best of luck!

~Jodi