How to stop worrying about my brother situation?

We are close than ever but it’s so painful for me to watch. He’s in the military and I told him it’s so hard for me to watch. They were fine until he started climbing the ladder. I want him to see his worth and it’s hard. Her actions behind his back could create losses. it’s like he’s back in Afghanistan again when he return home. He gotta outsmart her in something or participate in some kind of plotting situation. She loves to manipulate, destroy, and brainwash. She wants to be in control of everything and make everyone look bad. She uses people for information about my brother when he blocks her number. She been around her since 3. She publicly made my niece mom absolutely horrible to the public. She tries to take what her birth mom did and turn into a lie. My brother wife brags to the world that he’s a horrible husband, father and etc. then she goes back again to use him for attention. It’s been hell since he got that promotion and his dream job. She has been trying to take everything he ever worked for in life. She blindsided my brother completely. she has no other place to stay and can’t afford to take care of the children by herself. She works a 9-5 but doesn’t make enough. She wants other people to take care of the kids and buy them things. She constantly complains about how he doesn’t treat their kids like his older daughter. My niece can’t visit her dad without the wife. She tells her mom everything. She always come up with these sad stories about how she misses her mom, dad, and sister. It’s a sad story for attention all the time. This happens everytime she doesn’t get attention. then she start posting photos of my brother and her online. She thinks everyone is jealous of her. She told my brother daughter to block me on Facebook and then told her to unblock me so I can see the picture of them together. Then my brother wife deleted me. She’s jealous that I’m speaking to my niece mother. She plotted on my brother behind his back and made it about the money.

Updates
11 mo
I didn’t mean to post anon but it hurts my heart so bad. I have never in my life met a woman this level of evil. He got cameras all around his house and thinking about putting them on the inside. She has nowhere to go, no money or anything for support. So she does as she pleases…according to her
How to stop worrying about my brother situation?
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