You need to get those momma cats spayed! If they are feral (wild), there are organizations that may trap, spay and release them. If kittens and cats are dying, they are probably sick, and passing the sicknesses on to their kittens, and to each other. These cats NEED to be seen by a vet, or someone who can help them. Letting them stay the way they are will create more sadness and sickness and dying kittens and cats. I cannot stress this enough. Please!!!!! contact a shelter near you, if there is no shelter nearby, ask a local veterinarian for help.