The adoption was a catastrophe. Can I convince daughter to keep baby?

Right now, my daughter is going through some things and I'm trying to help her as best I can. She just gave birth 2 weeks ago to my grandson (Brenden). She's only 17. When she first told me she was pregnant, I was so angry with her, probably as angry as I've ever been in my life. I never thought my baby would be going through something like this. I immediately asked what she wanted to do and she said she was going to give the baby up for adoption. Her and her boyfriend had me drive them to the agency and started looking for people to adopt the baby. Over the last few months, I've been real distant from her. I'm more angry at myself than her. I feel like I failed in some way and I wasn't sure how to deal with it. I went to a support group for parents of pregnant teens, but it really didn't help at all. 5 months ago, we met "Lindy" and "Michael" and I immediately hated them. Something just seemed off. Their lives just seemed a little too perfect and there was something about Lindy that I just didn't like, but my daughter thought they were okay, so I kept my mouth shut. Over time, that hatred grew. First one lie after another (little lies but still), we'd ask them to meet somewhere and they'd never show and those 2 were always fighting about something and usually something stupid. I mean, it was pretty obvious that these 2 weren't ready for a child, but my daughter didn't want to see what I saw. The moment of truth came the day she gave birth. Me, her father, grandmother, and boyfriend were there. Guess who wasn't? Lindy kept calling to say "I'm 5 minutes away" and she didn't show up until an hour before my daughter was discharged. She was in the hospital 4 days and they lived like 20 minutes away. Lindy finally showed up and looked like she was hungover. She told us that Michael left and they're getting a divorce and then she was hysterical. She had to be escorted from the hospital premises, it was nuts! Mia and Gabriel were very upset, we all were. We ended up taking the baby home with us. Lindy came over the next day wanting the baby. I don't know why, but Mia let Lindy talk her into going through with the adoption and gave her the baby. 2 days later, Lindy came back and left the baby on the doorstep! A note stating "she couldn't take it anymore." How in the hell are people like this qualified to adopt? If I ever see that b*tch again, I will snap. The last couple weeks, Mia and Gabriel have been taking care of the baby but yesterday the adoption agency from Satan called and said that they have another couple willing to adopt the baby. I won't even repeat the cursing words I said to the guy. Mia said that she called them. I asked why and she said "because the baby would be better off elsewhere" and I said what makes you think that and she said "you. You hate me now." I told her I could never hate her, but that I was angry and she started arguing with me, took the baby and went to her dad's house. This has been very exhausting on all of us and I'm ready for it to end. I should have been more supportive. After this disaster, I'm convinced the baby will be better off with her than anyone else. We can financially provide for the baby and Gabriel's parents don't want the baby to be adopted either. I know her and Gabriel love this baby and want him very much so if there anything I can say?