Sister Trouble

My baby sister and I have always been pretty close.  She moved to Sprngfield about three years ago so we don't see each other much.  She has been with a guy for 12 years and has two children with them.  She was working at a company for about a year and a half making VERY good money.  How she landed that job, without any college background, I have no idea.  She is very smart though.  She has to be, to be at the rate of pay she was at.  Anyways, she had a lot of trouble at work with her boss, and she walked away.  I don't know what she was thinking.  Jobs are not that easy to find these days, especially if you don't have a college degree, and they don't pay enough.  She has found a job, but has taken a HUGE cut in pay.  Since then, she has kicked her looser boyfriend out.  He hardly ever worked, and when he did, he wouldn't pay his bills.  (That's the main reason she kicked him out.)  He ended up moving in with a couple of different girls in the past year until he finally met "the one".  The kids hated to be around her.  My oldest nephew, that is eight, told me that she was mean to him and his five year old sister.  Tonight, I found out that she grabbed him by the arm and threatened to break it.  I was furious!  I guess their dad has moved out from her, but that was not the reason.  I called my sister to get his number, but he was at my sisters house.  She wouldn't let me talk to him.  She don't want me to bud into her business.  She promises me that she is taking care of it.  I just want to talk to him.  He should not let anyone do that to his children.  I feel like those kids need me to stand up for them.  I know my sister is, but I need to too.  It was very hurtful when she told me to stay out of her business.  There are too many crazy things that happen to children.  When they are my own flesh and blood, I want to do whatever I can to protect them.  I am disappointed that my sister thinks that that is getting in her business.  I hope that it doesn't cause problems with me and my sister from now on.  I love my sister and I will do anything to help her and those kids.  Sorry, just thought I would share.