Breeder/litter question

[Katiesmithy]

Hi everyone, just a quick one, have been to visit a litter of maine coon kittens today but one of the girls has a kidney issue which has caused her to drop half of her body weight. The other kittens are perfectly healthy and fine, however i am concerned this may pose a problem for the kitten that we want and her health in the future. Is there anyone with any further information about this or that could provide some advice please?