Thanks Nanban. There will only be a couple more years and he will be 14 and more able to assert his feelings and opinions. At present, it must be easier for him to say the right things to please his mum, who can be highly volatile, than hurting his dad's feelings, as he won't take revenge or say anything spiteful in retaliation.
It's so tempting to challenge her when she comes out with lies, or distorts what has been said, but it won't be me who gets it in the neck. A couple of days ago she told me on the phone that my grandson had said to her that we would only give him presents if he can see his dad at Christmas. This is when she withdrew the contact tomorrow and texted me to ask when the presents were being brought round. It's her way of proving she has power over everyone because my grandson lives with her. She insisted my grandson came to the phone, and when he denied that he had said that to her, she sent him from the room. She had distorted my casual comment 'your daddy is looking forward to giving you your presents.' Every now and then, I see that little flicker of recognition that shows me my grandson has grasped what her behaviour is like towards us, but I would never say anything to him - he will decide for himself who he can trust as he grows.
So, there will be a gaping hole where my beloved grandson should be this Christmas and we hope to see him in a week or so, if things settle down again. It's what he wants, and the divorce should be sorted soon, with an opportunity to get contact officially agreed at the court. Makes you want to weep, doesn't it?