Mother just announced she is moving to FL at the end of the week, we are other household and scrambling to figure out what to do

We are in PA. I am the step mother of 6YO girl, have been since she was 1, total center of my universe. We have had a good relationship with the mom, never had to go to court, she gets child support every week, and she and I had become quite close friends. She also has a 3 YO with a now ex who is heavily medicated, severely bipolar and has a history of incarceration for fighting. Their relationship was very volatile when they were together, constant fights, we'd hear about it from kiddo, even up to throwing things. Definitely started to affect kiddo's behavior too. Mother for some insane reason thinks she's more miserable without him, and can't handle life without making it work with him, etc. We were very calm but vocal in our opposition, citing the fact that she is ripping her children from everything they know and love, taking her from her father and second mother, that from a psychological standpoint she hasn't given herself as much as 6 months to heal from that breakup and tumultuous relationship and making such a huge life decision is ill advised. When asked if she had spoken to anyone else around her or a professional about this to get advice, she said No, she knew they would just tell her not to go. So maybe there's something TO that....?! I digress. She first said "Well, we'll see what 6YO wants to do.." No, full stop, 6YO is not emotionally mature enough to make a decision like that. In Mom's ideal world, kiddo stays with us for the rest of the school year and some summer, then goes down there and enrolls. We get her summers and winter vacations. Over my dead body is my kid going to live with mom and her unstable ex at his dads house in where there is already another special needs teenager and 1000 miles away. So, trying to recover emotionally from this bomb that was dropped last night and take practical steps. There's a very good chance that Mom will get down there and turn right back around in a couple months, realizing it isn't worth it, but I don't want to count on that. On paper, our household and life circumstance are miles better than moms. Stable jobs for 4+ years, enough income to make ends meet and support kiddo full time(It would be tight but doable). Realistically, I know mom's behavior doesn't reflect well on her in the courts eyes, especially the choice to take her kids suddenly and move across the country and in with a violent offender with mental health issues and a record. If it looks like she's really going to take this the distance, what are our next steps? We have no experience or financial ability to hire a lawyer, and are happy to do what we can on our own, I just don't even know where to start. Obviously we want to make this as easy for kiddo as possible, but don't know what to do short of never speaking negatively of her mom around her, and being there for her as much as we can, doing more family activities together, etc. This whole time I'm just so incredibly heartbroken over how much this will impact the 2 girls. via /r/Parenting http://ift.tt/2jUGzdA