If she's not nursing the babies at all you need to start asap. I don't know if you have access to kitten milk replacement or goat's milk, but you can bottle or dropper feed them with that. No cows milk. If she is nursing them, you need to keep her with them, even if she is struggling. That is going to be their best chance for survival if she will feed them. Bottle fed babies don't always have a high survival rate. I'm sorry that you are having such a terrible experience. The babies will me to eat every 1 to 3 hours, like human babies, and they will need to be kept warm if mom is not with them. The best case scenario is if she will stay with them. I'm sure that other people will have advice here to, good luck and let us know what happens.