I think, if I were in your shoes, I would say "I'm sorry you feel the way that you do. It's never too late to speak to an IC about the issues you have and maybe the therapist could help you find a way to reconnect w/your daughters."

Bounce that ball back into her court. It's not your job to make her happy and help her now.

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.