I think you are very wise not to contact her again. You've given her the thumb drive, so now it's up to her to build a relationship w/her daughters.
She's dealing w/a lot on her plate at the moment...however, stating what she did about her father was manipulation on her part. She is still looking for that illusive key to unlock the door for her to have a relationship w/you and the girls...but she's going about it the wrong way. Unfortunately, by stating what she did about her father will not gain trust w/you if he's doing fairly well at the moment. She is feeling sorry for herself and is looking for empathy and yes, even sympathy. I know I may sound harsh in this...but she's got to bottom out.
I'm so sorry she's still "out there". I'm glad you are going to go see your father-in-law and the girls want to go to. At least you can visit w/him and actually see where he is in his health crisis for yourself. No one knows who the man upstairs will call us home and who knows your visit may just cheer him up a bit.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
