Simon, I'm glad to see you came back to post. I'm sorry to see that things haven't improved w/the wife and the son. Yep, they are a very unhappy bunch, but they are the ones that will need to find a way to "dig" out of their mess.
Hope all is well w/you and 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.
