These are the two messages I thought about sending him:
1) H I understand you want to see the girls during this family time that is Xmas, unfortunately some actions have led to the break up of our family unit and I don't feel it is right to pretend with our children. You are more than welcome to FaceTime them when they open their presents, and you can have them as long as you wish on Boxing Day.
2) H I understand that during this festive season you want to see our girls on their special day, unfortunately it has been a while since you lived with us I have made other arrangements. I will be more than happy to FaceTime you when they open their presents and you are welcome to keep them as long as you wish on Boxibg Day!