just don't know what to do

I'm so upset right now, I can't cry in front of my brother because it'll make him worse. So here's a little back story: about 4 years ago he got with this girl and they seemed happy. He was in the army and stationed 5 hours away from us. She was from where they were stationed. she had a one year old son when my brother met her and his father wasn't in his life, so my bro decided to bring him up as his own, and oh my god he loves that child more than anything. they decided to move back home because it would give their son a better life being in the country than being in the city. fast forward a few years and they have a daughter of their own who is now 2. when their daughter was 2 months old, my bros girlfriend just up and left them all. leaving my brother with his 2 children to raise, she left them for another man, who at the time had a pregnant girlfriend who he left as well. She saw her children once every 2 weeks, she always made excuses not to see them. my bro did an amazing job raising them. they are the sweetest children you could ever meet. Well anyway, she came back about a month ago and decided she wanted to be a good mother, my brother being my brother and wanting their children to know their mother, let her. it turns out that she and this guy have broken up because he's gone back to his baby mama. And she's taking the kids back to the city 5 hours away. my brother tried taking her to court and isn't entitled to keep them because it means that the kids would be split up and he has no right over his son biologically. He's losing his children and we are all devasted. He's raised them both. I'm 32 weeks pregnant and I'm stressing and uncontrollable. I just don't know what to do. sorry about the long post, I cant vent to my family because we are all devastated about it.