Anyone else??

SOOOOO I'm basically raising my two niece's and one nephew have Ben for a couple of years and now that there living here it's even more so I have pottyed trained the older two and just now finished the 2yearold but is it weird that I wish I could get custody of the 2 years old shes blood the older two aren't I love them too but I want her more then the other two the other two act like wiled animals when she's around and the oldest is her fav I have alot on her but I do on my brother as well but I don't want to bring a wall up if I do one day and loose I might not ever see her again???? She's a real nut job I think she might be bipolar but not sure....It could just be her....