Hi Baloo107, welcome to the group. You're not alone here in being a caring grandparent who wants to protect the grandkids caught up in all of this.
Just a few questions as we get to know more about you and your situation:
How long have you suspected your D has BPD (whether enough for an official diagnosis, or "just" traits and behaviors)?
What's your relationship with the grandkids' dad like?
What's your relationship with the grandkids like, and how old are they? Do they live close by?
It's really difficult to have some perspective that professional help would be a good thing, yet not to have the leverage to make it happen directly. In fact, it sounds like you're aware that a direct approach might not be the most effective, as I read that you're looking for a more "gentle" approach.
Have you checked out our article and video on
Anosognosia and Getting a "Borderline" into Therapy yet? Give it a look when you have time, and let us know your thoughts, especially if it rings true to your situation.
Glad you're here -- keep us posted on how you're doing.
kells76