I wonder how much their dad really wants this time with them. What are his motives for this huge change?
Is he still an active A? What kind of behavior would you expect from him towards the children?
Do the children have a therapist?
I will reread your older posts, but it would be helpful to get your most recent conjectures.
In the meantime, just think about today, ok?! This could just be a passing thing with him?