Heather, Here's another suggestion and it just might work. Instead of him taking her out to lunch, why not have a nice lunch prepared there for them to sit down and eat together? That way she is still in her "safe" environment and you aren't too far away.
I realize you probably don't want to do this...but I'm trying to think of ways to bridge the gap and make it more pleasant for your daughter.
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.
