Hi unsinkable. I don't know what you can do about your grandchildren's situation, sometimes child protective services helps and sometimes it doesn't. They are so overwhelmed, they can't always give each case the attention it deserves.
In my state, however, anyone can petition for guardianship of a minor, even non-relatives. That is what happened here, although there was also a neglect/abuse investigation in progress.
It can't be easy for you, with them being so far away. At least if they were nearby you could help out, or at least check in from time to time (assuming the parents let you).
Sometimes I don't understand why they say that being a grandparent is so much better than being a parent! You still have the deepest love & concern for these children, but no control and often not that much influence over their fates.
To answer your questions: my son and his fiance split up, and a few short months later my granddaughter was taken to the hospital with multiple skull fractures and a small brain bleed (she is OK now). The injuries were apparently caused by the mom's new boyfriend.
While my husband & I went to be with our granddaughter in the hospital, without telling anyone else the maternal grandfather went to the court, filed for, & was granted guardianship. We fought it in court but lost.
Around the time of the break up, I began to realize that my son has issues that go deeper than simple pot smoking. Due to family history and my own observations, I think he most likely has BPD.
As unreliable as he is, and as angry as he makes me, I still do not think he should be permanently separated from his daughter (he has never harmed her). But that seems to be the maternal grandfather's ultimate plan. This guy is a pure narcissist who has shown zero concern for my granddaughter's feelings - he just plucked her out of her life and all that she knew and stated point blank "she'll get used to it." He has changed all of her routines & taken away all of her former sources of comfort, like toys, blankets, dolls, and worse of all, the people who care for her.
The whole thing has been beyond heart breaking.
I hope you can find some way to deal with your situation. It's so hard. The only way I get through it is to remind myself that I'm not going to live forever, so somebody else is going to HAVE TO step up to the plate eventually. Better it gets sorted out sooner rather than later.
I hope whatever way it goes, my granddaughter has a good life. I hope the same for your grandkids too!