Hi mrcat
Welcome to bpdfamily! Having a BPD mother can be quite difficult, BPD is a challenging disorder and I can imagine that her current health issues only make matters worse. Could you tell us a bit more about your mother's behavior that leads you to believe she has BPD?
The behavior you describe of one moment being regarded as an 'angel' and the next as 'horrible', sounds like the BPD-behavior known as 'splitting':
Splitting refers to a primitive defense mechanism characterized by a polarization of good feelings and bad feelings, of love and hate, of attachment and rejection.
Splitting is a powerful unconscious force that manifests to protect against anxiety. Rather than providing real protection, splitting leads to destructive behavior and turmoil, and the often confused reactions by those who try to help.
You can read more about splitting here:
BPD BEHAVIORS: SplittingIt isn't pleasant to be called a horrible person by one's own parent. I have a undiagnosed BPD mother and sister myself and what helps me cope is to keep telling myself that no matter what they say or do, it isn't a reflection of who I really am but only a reflection of their own inner turmoil and fantasy world. Whether they call me angelic or completely demonize me, it isn't a reflection of who I really am.