Oh wow. What a mess! I'm so sorry! I hope this all blows over soon.
I don't blame DH for being angry, but if only he had stuck to the issues - the late cancellation and how DD treated you - and not made accusations! But I know people don't always think when they are angry.
He needs to apologize for that if he wants to see the grands again any time soon. If he doesn't care to do it for himself, he should do it for you. I think Falconbird is right that your DD will come around, after a while. However, it might happen sooner if he makes a sincere apology.
I hope you were able to attend GD's party on Sunday, after all. If not, I know it may be hard for you to turn around and say, "Of course, we'll babysit." If you do, you may discover that DD is no longer interested, unfortunately. It's worth a try, I think, but you may end up having to wait till DD reaches out to you again.
If it helps at all, I'm another one feels that AC often try to take advantage. At some point, you'll have to let DD know that you and DH have your own lives and need to be asked in advance. Now is obviously not the time though.