
Welcome.
You are not alone. As painful and complicated as things are for you and your family there are many families here that really do understand. I encourage you to continue to reach out and get support from others.
It is common for BPD moms to be overwhelmed with caring for children which makes sense when viewed in light of they have their hands full trying to cope with their own emotions and self. Our D lost custody/visitation with her children and has lots of self hate/blame/shame that she is a 'bad' mom. Just a thought about how your D may see things.
Time may be your friend. Does your D cycle up/down? Can you stay open to contact?
Perhaps focusing on the good relationship you have with the other 2 g-daughters will carry you until things change with your D. And in between it may help to boost your communication skills to be prepared for when she reaches out to you.
Wishing you peace and gentleness.