What am I supposed to do?

So my brother is attempting to recover again from his Heroin addiction. His girlfriend is sober but INSANE. She cuts him off from the world thinking it will help and he lets it happen because she financially is taking care of him now. It’s to the point I have them both blocked on everything and now from this new number they have.

She won’t let him talk to me or our mother because she has some serious mommy issues and rages anytime he shows an ounce of kindness to us. I’m due in 5 weeks and even after a year I’m still waking up to shit like this even though I’ve blocked them and changed my number. I won’t talk to him for weeks or even at all and I get sent shit like this. I can’t even let him near our starting family at this point and I don’t know how to curb this bullshit when she pretends to be him.

What can I do? She’s cut him off from every support system he can use and I’m still getting verbally abused regardless of how far I stay away from them.