Dearest Shelley... peace to you... and may I say:
LOVE her... and let her go. Let her know you are "there" for her CHILDREN... not to randomly babysit them, as they are her children to look after... or to cloth/feed them (at least, not primarily, but they ARE your grandchildren)... but that they are her responsibility and she is her own responsibility... or the boyfriend's... based on HER own choices.
Whenever you see her... you, your husband... and your other children... don't yell at her or roll your eyes or let her know just how disappointed/disgusted you may be in her, for that would most unloving and unkind on YOUR part. Rather, just hug her and let her know you love her, IN SPITE of her poor choices and errors in judgment. For who of us don't want to be loved in spite of ours? And who of us are without them? Sure, some more than others... but, what, can you "rate" poor judgment and error if you truly LOVE someone?
Unlike the 'hateful' teachings of the WTBTS, rather than 'shame' others into doing good, we must LOVE them into it; not conquer good with evil, but evil with good. If, then, you are good to your daughter, in spite of her rebelliousness and poor attitude, she will SEE that good... eventually... in YOUR goods works toward her... and will eventually learn it herself. If not, however, she will only LEARN to perpetuate her poor thinking further, perhaps even to the detriment of your grandchildren, which MIGHT end up in you having to care for them primarily! And the boyfriend will help, trust me. No, you most certainly want to avoid that, yes?!
It is not your primary responsibility to provide for her... or her children... but it is your SECONDARY responsibility, as they are your flesh. True, you did not choose to have such responsibility at this time, but you CHOSE to have a daughter... and "life is like a box of chocolates - you never know what you're gonna get!" Thus, the "choice" YOU made... has made IT'S choice. Additionally, it is NOT "good" for YOU... to "close the door of your tender compassion" on anyone... particularly on your own flesh for it us YOU who will pay... with heartache worse than what you know now. For you will not be able to be yourself, but what you are allowing another's CHOICE to make you be. It's not worth it, though.
Yet, if you take PRIMARY responsibility out of her control, do for her and her children what SHE must now do, she will never LEARN it. Now, if she needs you to babysit in order to work or go to school... and you can do it... do it. LOVE...for her and for your grandchildren (whether you 'wanted' them or not)... will let you do it, happily, without complaint. If, however, she wants you to sit so that she... and/or boyfriend... can have a "night out"... uh-uh. No way! That's not your responsibility. THEY chose to do an "act" that resulted in a little person that must be cared for... so it is THEY who must give up their social life and provide such care. You're not being "mean" (which might be tried, but don't let them "handle" you with that melarkey), but it's the result of their CHOICE. Tell them that.
You and your husband are the ones who must now TRULY be mature. To argue, scream, curse, lose your temper, etc... what benefit it there in it? What benefit was there? Nothing. What happened... has happened. Twice. Ah, well. NOW... you must "see" how to handle the matter so that YOU are not the 'victim'... but the 'teacher'... the ADULT... the parent. She is again a parent and now must learn HOW to be one... even in the most trying of times... from you!
Again, I bid you peace,
Your servant and a slave of Christ,
SJ