Some perspective for your youngest daughter: the only way it works for grandparents to take care of the grandkids is for parents to lose custody. That is, IF grandparents choose to take on the full-time role of "parenting" the grandkids, and IF the courts grant them sole custody... then it can work - but no guarantees.
The current situation doesn't help the grandkids. You don't get to actually CARE for them. They know you love them, and that you will do what you can. But what you CAN do is highly limited because of their parents... and because of the other people in your home.
Sending hugs.
