To give a bit of backstory, I have DS10 with my ex. I have very limited contact with my ex as it always ends up with him arguing. He doesn't help with medical appointments, haircuts, homework, contribute towards school uniform, come to parents evening etc.
In the last year he has gone from having DS10 9 nights a month, to 6, and now 4. The most recent reeducation was due to his 4 year old starting school and between the other DC there he can no longer get our DS to or from school. This does mean that even on the weekends he has him I still have to collect him from school on the Friday. DS now goes every other weekend but my ex is a shift worker so sometimes he is at work when he has our DS.
Bearing all of this in mind, DS feels like his Dad doesn't care about him anymore and prefers his new children.
We always take turns at Christmas. One has DS Xmas Eve and then we swap on Xmas Day at lunchtime. This year it's my turn to have him Xmas Eve.
DS has turned round and said he wants to stay with me for all of Xmas this year and see his Dad on Boxing Day instead.
This will not be well received by my ex and I will undoubtedly get accusations of brainwashing DS.
IABU - I should tell DS that he has to go to his Dad's Xmas Day as it is his turn and we need to stick to the arrangement to make it fair.
IANBU - I should tell DS that it is fine for him to stay with me for all of Xmas (as he feels completely unwanted by his Dad).