My daughter's children ended up in FOSTER HOMES. What would YOU do in this situation?

This is lengthy, but I please read it because I am at wit's end. On August 4th, my daughter's husband tried to have her committed to a mental institution through a court order. She (age 22) was picked up by a police car at 9AM and taken to the institution. She called me crying from the back of the police car and wanted me to come to the institution which I had no problem doing. They found no reason to keep her and sent her home. While she was gone, he and his mother changed the locks on the house so she couldn't get back in. When the police brought her back home, her husband did let her in to get personal belongings. While there, she picked up her 18 month old. The mother-n-law shoved my daughter into the wall while the child was in her arms and tried to jerk the child out of her arms hurting his arm. Once outside, the mother-n-law pinned HER up against a vehicle screaming at her. The little boy in my daughter's arms was crying because he was scared. I got the child out from between them and took him to MY vehicle. You would think that if she were so concerned about the child she would have come after me, but instead she continued the attack on my daughter. We took the child to the Emergency Room to have his arm checked out. Naturally anytime there is an altercation like that police have to be contacted by the hospital. The mother-n-law by that time had called the DHS hotline, lied and said my daughter HAD been committed, refused, escaped and kidnapped the child. She knew this wasn't true because she was there when the police returned her back home. My grandson was taken into DHS custody for a 72 hour hold but ended up being gone 1-1/2 months going to sleep and waking up in stranger's home. This broke my heart for him. I immediately went to the ends of the earth to get him back, filing to be a Provisional Foster Parent which I did get and eventually he AND her premature twins who were born 4 months early in January and were still in the hospital in August on the day all this happened. At the adjudication hearing, my daughter was returned custody of her children since DHS investigated and found out everything the mother-n-law said to be a lie and would not return to children to that environment where it was dark constantly with no sunlight ever coming in PLUS numerous other issues. Oh, btw, my daughter is pregnant again and WAS on the day he kicked her out and he KNEW that. He has threatned to kill people (even me) and threatened to degut a family that included even a tiny infant (he only told my daughter this). My daughter made all this be known on the witness stand. DHS returned custody to my daughter with the understanding that she live with me so we now have moved from my small apartment to a larger house to have room for all of us. Her 18 year old sister also lives with us and helps out with the children a lot. This caused my to break my lease and now have to pay close to $2000,00 in liquidated damages for breaking the lease early.

NOW, my daughter was contacted a week ago yesterday by this jerk wanting to know if we needed anything for the children, and since then she has been spending a lot of time with him. I know she has been telling other people they are thinking about working things out and getting back together, BUT she tells me different. I'm sure she tells me what she wants me to hear. I have tried to convince her that I feel he is just telling her a lot of bull to gain her trust back just so he can get the children again, then I feel this would happen all over again. Both of the twins get a big SSI check because of their special needs. They are 9 months old, one is on oxygen with a shunt in her brain and the other has had to have a surgically implanted feeding tube. They are BOTH going to have to be placed in glasses within the next months. DHS has said that if she goes back to him, the children will remain with me and NOT go with them, but she STILL continues to hang around with him thinking that will eventually change. I don't understand how she can even WANT to be around the people that caused all of this to begin with causing her children to be put in foster homes. She thinks he has changed, but I don't think he is capable of changing, not that fast anyway. She says they are trying to be civil for the children, but I don't think he can be trusted. What is your opinion and what would you do to try and convince her that she is making a big mistake. Now he has her on HIS side and she claims that DHS was illegal iin allowing me to have the children. DHS tells me things, but they say they are told something totally different. I find that hard to believe.