I have to agree with SingleGirl. No need to create a problem if one doesn't exist. Young children can be very resilient, especially when they have concerned, aware, loving, supportive parents, and regular routines ant things continue as always. If problems become apparent, let the child talk about what she needs to talk about, and validate what she feels.

I'm worried about the older child, who is still a young child too, and apparently has a pretty chaotic life and maybe less than supportive parents. I hope they get some help for her. Children at six don't just rebel and try to hurt their mom, or claim to have molested another child (unless afraid of being punished for lying if she denied it) for no reason. Whether she did it or not, there is something going on there that isn't right.