Also, not going to condemn you and say that this child is not God's will. God most certainly allowed in his permissive will for this to take place. Imagine some here telling this child the child is not of God's will! How unwise!
P38mom - in light of your revelation of the sexual abuse, wow, there's a lot going on here and that sheds a lot of light on the situation. Is your daughter afraid that you're not doing enough to protect your son from something like that happening to him? Victims of abuse often become hyper vigilant and trauma changes thought processes. Trauma brains think very differently and to "normal" people, it can seem extremely illogical and be very hard to understand. I'm guessing this might go deeper rooted issue or fear here. Her criticism of you might be a cry for help, she might have things going on in her brain or with her emotions that she really doesn't know what to do with and can't cope with. It's certainly possible that is where it's coming out. It's also very possible that the trauma you experienced is affecting your parenting and maybe your daughter is seeing something you aren't.
I'm praying for you and your family.