I would contact the Humane Society and let them know
of the situation as quickly as possible. Often, if the cats and
kittens are deemed suitable for adoption, they will spay them, vaccinate them, and nurse them back to health if they do have problems.
And then the cats won't have to be strays anymore. They will have homes.
Please do this. Stray cats do not have an easy life, and die young from disease, injury, or starvation.