Welcome crazedmom. I split off your reply into it's own topic and gave it it's own title, so everyone could find it and answer you.
That's such a tough position to be in. You want to take care of the GC, but yet I agree with your DH, DD needs to help herself too. I think the offer of letting her move in until she could get back on her feet, was a great opportunity for her. Her adament rejecting of it, along with her attitude now of cutting off the entire family, says to me that she didn't want help...she wanted you to do it for her.
I applaud you for being willing to take the GC, as I know that you want what's best for them, but I have a personal philosophy for myself. I don't mind helping anyone as long as they are helping themselves. I don't believe in helping someone that refuses to take responsibility for their problems and are actively looking for solutions. That may sound harsh of me, but too many times have I tried to give or help someone to find out they were not trying to better themselves. An example that kind of pushed me over the edge: I had a co-worker with cancer and was upset because she was having trouble paying her doctor bills. I organized an event to get money for her to pay off her doctor bills. After it was over, she went and used the money to buy a full back tattoo and was showing it off to all of us.
If I was truly struggling with two kids and someone offered to take us in until I could get back on my feet, I would be grateful.