First of all, bless you for taking on the care of your three grands.

All three are in therapy and meds- that is huge, especially for the adult grands.
You reached out to us and welcome! This forum can be utilized as a network/ tool to obtain info, vent, etc. Familiarize yourself with the forum . Know that you can click on any name and get previous posts / back story of a person. Take a look at the drop down menus along the top for some topics
Some of us even get our own therapy ( i do) in order to learn more coping skills/ get more one on one help. i would like to throw out there 12 step programs for family members are free and they help with detaching from the BPD person. It is so easy to get embroiled in their drama, but trying to learn detachment ( without guilt) is a goal for most of us. We are here for you.. Also, for the 14 Year old, you can still talk with her therapist ( can't with the adult's therapists unless they give permission). There is a lot of hope. Please write back as often as you need.