Having a BPD parent myself I do know how hard it is to communicate.
Kids know where they can get comfort from and are very perceptive. It’s a really good thing that she only has on set days. Great idea for your son to write down the days she doesn’t adhere to the schedule.
I think you have the right balance in your thinking Krudula and have come to a level of acceptance that she is who she is and you can expend your energy on your GS (grandson).
Kids really want to be heard and their emotions validated rather than discounted.
There are great books on positive validation for children Krudula. We can do little to change the Borderlines behaviour however we can ensure the kids are validated.
I have read this one and thought it was great:
www.amazon.com/The-Power-Validation-Out-Control/dp/1608820335As for exDIL (ex daughter in law) – blame and accusations really are such a huge part of BPD – they relinquish their own feelings about themselves by projecting onto others. Part of the key is to not retaliate and counter-attack because it has nothing to do with you or your family – it’s her own emotions getting out of hand.
Boundaries however are important where you feel she has over stepped them. Simple boundary statements are always good to have in hand. If she blames and accuses a simple boundary statement is all you need.
Best phrases for setting boundaries How are you going?