There used to be people inside of CPS that one could get a hold of privately that would then be able to advocate for the kids without having them overwhelmed by the system. The people I know that did like that are long past retired. Otherwise that would be my suggestion.. but I don't know anyone that is still active in all that.
Without that, it sounds to me like the only option is to befriend the mom and help her in whatever way she will allow. Share a meal, a cup of coffee. Burrow into the situation, find out if there's family somewhere. Slowly, slow enough not to spook her. She must have parents that care? The father of the kids? But still, on the ground, in the moment, try to provide a safe haven for her as well as the kids. Obviously that's easier to think and write than it is to do, and oh man I feel for you, and all of them. Good luck.
Without that, it sounds to me like the only option is to befriend the mom and help her in whatever way she will allow. Share a meal, a cup of coffee. Burrow into the situation, find out if there's family somewhere. Slowly, slow enough not to spook her. She must have parents that care? The father of the kids? But still, on the ground, in the moment, try to provide a safe haven for her as well as the kids. Obviously that's easier to think and write than it is to do, and oh man I feel for you, and all of them. Good luck.