Hi Denita!
It is really hard to be in a situation where you have to choose between your kids, esp when you know one is hurting so badly and the other will force this to be a "her or me" decision.
Your younger child has been traumatized to an extreme by difficult child. There is no "slightly abused" when it comes to a difficult child, esp to how they treat a sibling. I am that sibling, with an adult gfgbro that I only recently had the cajones to cut out of my life. It is really hard. It is even harder to keep my parents OUT of it, though they are finally working toward that goal after his latest stunt. I hate hurting them, but they are adults. Gfgbro terrifies my kids to the point of panic attacks and nightmares and I had to choose my kids.
I don't know all of the things that happened between difficult child and pcgfg, and chances are neither do you. As long as there is contact the difficult child will continue to try to hurt pcgfg, simply because she feels she has a right to. Why does difficult child feel that? She is a difficult child.
I would guess that pcgfg feels very vulnerable, esp when difficult child is around. Knowing that difficult child can come into her home probably increases those feelings of vulnerability and being unsafe to a great degree. I would NOT be surprised if she is terrified every time difficult child comes over or she finds that difficult child has or will be there, EVEN IF SHE IS NOT THERE WHEN difficult child COMES OVER.
difficult child is old enough to find her own home outside of the house. Pcgfg is not. Do you remember how upset and scared you used to feel when difficult child would rage and pull her difficult child behaviors? Imagine being younger than her and having NO WHERE TO GO TO GET AWAY. There is nowhere that pcgfg can go to get away from difficult child for more than a little while. Your home should be her safe spot, her refuge. Knowing that difficult child can come into her refuge leaves her with a horrible unsafe feeling most of the time.
I would be highly surprised if difficult child did not find a way, at least sometimes, to let pcgfg know that she can "get" pcgfg anytime she wants, even at home. difficult child may even have told her that she is moving back in, that you will let her move in because the pregnancy and the little bit of safety pcgfg has had is going to be OVER. Pcgfg is probably terrified. It is one reason the therapist is probably encouraging you to change things.
At this point there is little that you are going to do that will have an effect on difficult child. Very little. She is 18 and can do what she wants.. Letting her move back in will make things much worse in the medium and long run, even if the short run is "okayish". She has already proven she will not take care of her child and she does not value her child. I would be very skeptical of any claims that she has "changed" simply because with-o a LOT of therapy given AFTER she hits bottom she will see no REASON why she should change. She LIKES doing the difficult child stuff at this point and she believes others will "rescue" her.
You still have a chance to help pcgfg become mostly easy child or all easy child and to have a decent, responsible, happy life. It IS going to take work and effort on her part, but as she is already working with a therapist and is at least partly easy child, I would say there is hope there. Before pcgfg can give up the difficult child behaviors she learned, she must feel SAFE. There is NO possibility of change unless she can feel that she is safe in her home and feel that you will choose her safety over difficult child's current crisis.
in my opinion you need to work out a way to see difficult child out of the house. If that means asking her to meet you at McD's for a burger with the baby, so be it. I would probably avoid telling difficult child not to come to the house for as long as I could, but if she pushed me I would tell her. Don't tell her that it is because pcgfg doesn't feel safe if difficult child can come to the house. Tell her that you would prefer to meet her elsewhere for another reason. If you tell her it is because pcgfg is scared, difficult child WILL find a way to "get" pcgfg and make her feel even worse. She will alsso use the unborn baby to yank your heartstrings. You and I both know that if she really cared about the child she is carrying she would have cared for the first child she had and want to see that child. As it is, she only asks to see her toddler when she wants something.
Maybe you can tell her that you want to meet her at McD's because you want to be sure she is eating, or something like that.
Either way, I would find a way to keep her out of the home so that pcgfg can have a chance. It may be part of what pcgfg needs to begin to shed the difficult child side. The difficult child behaviors of pcgfg were learned as a reaction to feeling very scared of difficult child, at least partly.
I am so sorry you are in this situation. Esp with difficult child having another child. Do you think difficult child got pregnant with the idea of using the baby to force you to let her move back in at home? I know a couple of difficult children who have done this. I hope she is signed up for some sort of program like WIC so that someone is keeping an eye on her unborn child.
You have done so much for difficult child, worked so hard to be able to help her. She had thrown all of it in your face, time and again. Pcgfg has done some of that, I am sure. She learned it was okay by seeing difficult child do so much of it. Right now pcgfg is your responsiblity to take care of. difficult child and her unborn child are difficult child's responsibility. You need to put what pcgfg needs as your priority. difficult children do so much damage to our pcs. difficult children make SURE they get most of the attention, resources, everything and pcs are often traumatized by them in many many ways, much of these ways (if not most) are ones we parents NEVER see because difficult children overshadow the pcs' needs. At some point we MUST make healing our pcs a priority over whatever is going on with difficult child.
Otherwise difficult children end up wreaking havoc on many many aspects of our pcs, even to the point of pushing them to gfgness.
This is my 2 cents from being the younger sib of a difficult child. And from raising a difficult child who did a LOT of damage to his siblings.
(Sometimes making the difficult child KNOW that you are putting the well being of the pcs ahead of them no matter what they do helps the difficult child to start to turn things around. Wiz told me that realizing that I would put making the other kids feel safe above trying to "reach" him was the turning point for him, and was a big enough shock to help him really LOOK at himself AFTER he spent several months acting out his rage at being thrown out and me not allowing the judge to force us to take him back into our home.)