WR, Very nice responses...no pressure on him and I think as long as the texts remain neutral, he'll act like he's got some sense. He doesn't feel as if you are keeping his sons from him and this is a good start for building a co-parenting relationship.
Stay the course.
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.