My friend has two children ages two and four. The girl who is four, seems very oppositional. She literally starts every sentence with "No" when you make a comment or ask her a question. She is and has always been jealous of her brother and antagonizes him to the point of him biting her. Now a new baby has arrived which she has dreaded from the start so she is particularly angry today. She was verbally nasty to me and when anyone asked her today about the baby she refused to answer. My friend is getting quite frustrated with her and I tried to explain the expectation of regression, accidents happening, acting out, lying and just outright non compliance(which has been an issue before baby was conceived minus the accidents) and that she needs to be more attentive as far as communication, including her in baby care etc. I am not around enough to see the full interaction between mother and daughter, but I am out of the obvious tactics for this behavior and because I have noticed the hostile feelings towards the brother after two years of having him around, I am concerned about deeper issues. I forgot to mention that the mother says things like, "I get along better will my son" and ""When the she asks me a mil and one questions while doing housework, I tell her to stop with all the questions, I'm busy". So that may be a clue. They are a very religious couple and are very gentle and sweet. I just want to help her out before she gets too frustrated.