We've got no examples of _how_ the 14 year old is a spoiled brat. All we know is that her mother has taken her on trips. That is not spoiling her. If you feel that the trips are being taken to the detriment of your father don't blame the kid, it's on her mother. And if you want help with your dad then ask. Don't lash out at the kid. Of course her mother is going to defend her. You might be tired and overwhelmed but it sounds like you are also seething with jealousy and anger that your niece is having fun. And why should she step up? She's 14. That is something to direct at her mother.