Jo, I would tug gently on the mother and see if she is still stable in the soil. She may just pull out easily if she is rotting. If mother is pulled out, you can still leave the babies as is, just tuck more of your rock under/around them. If mother is still stable, take the soft leaves off and tuck more grit underneath all. (Hope these aren't the beautiful purple ones that I have been admiring?)
Good luck!
