My heart goes out to you, too, nannynoo. Sounds as if you have really been there for gs and have been a Godsend for him. It's wonderful to hear how much you've helped him, and I'm sorry you're going through such a hard time right now.
Have to agree with other posters that just because dd hopes/wishes/says that something will happen soon doesn't mean it will. It seems like you have some time.
It's good in a way that she wants her child back and is working towards that. Would you be happier if she didn't care? I don't think so. But she does seem to be "getting ahead of herself," as you say.
If she does get gs back, though, she will then be in charge of him. So I hope you maintain a good relationship with her. Otherwise, I'm afraid she might keep gs from you, which wouldn't be good for him, imo, and, of course, would hurt you, as well. I see that you say he will "always have a back up with" you. Great! But if dd gets angry with you, you might not get to see him while he's living with her. You must let ss know of your concerns, of course, for gs' sake. But please be careful that dd doesn't get the impression that you're against her having him at all.