Please seek legal guardianship of your grandchild then, when you legally have a court order, you can deny her visitation.
And here's why. If you allow this child to go with her, anywhere.
When we got guardianship of our grand kids the judge sat us down in his chambers. He told us several things. He said we'd come to him to say my daughter was unfit, he was agreeing with us, he said that we would not be responsible for them totally, that if we let the grand kids even walk around Walmart while we were there and one of them stubbed their toe that he would make sure that he came after us with every legal power he could.
He was trying to get us to understand that we said she was unfit, he agreed, but if we let the kids go with her for any reason or see her and she acted out that WE were the ones that were being neglectful and WE were the ones allowing them to be in a dangerous situation.
Your daughter doesn't sound stable and if she's not stable she can't be around the kiddo. Period. YOU could be held legally responsible.
Another grandparent raising grandchildren that I know allowed her son, who was doing very well, to take his kids to his house for a visit. Their mom showed up, he let her see the kids, the court found out the kids were around this mom and they took the grandkids away from this other grandmother and put them in foster care since the dad obviously wasn't going to protect them from the mom either.
Letting your daughter see her kiddo can come back to bite you in the butt. If you don't have legal, court ordered, judge signed, registered with the court clerk, notarized court papers that say you have the right to keep her child from her then she can file charges on you and have you arrested for interfering with her parental rights.
So one way or the other you have to make a change. Either have legal guardianship and keep those kids from her until she's stable or go get legal guardianship while she's homeless and the court will side with you without much investigation.