To not give our 10 year old his Christmas presents?

I don’t think ruining the day for the whole family is the way to go. However it’s time to have a major rethink on how you are managing his behaviour as it’s currently not going well. Him making threats and you making counter threats is pretty futile.

What kind of support have you had with this?

It sounds like you're having a hard time with your son and it also sounds to me like there are deeper issues going on with your son. Please give him his presents and don't use Christmas as a means to control his behaviour. I think that could further damage your relationship with him.

Just stay really calm and tell him you'll just tell her he's trying to spoil Christmas if he says anything, and that his consequences are not a choice.

(But leave his presents out of it).

Have you tried to find out the cause of his aggression? Did it start around the time you were pregnant / his sister was born?

You are bargaining with him stop doing that he is 10 years old! remove consequences and say well if you want to do it carry on but you will upset your brother.

I would tell him to tell her and see what the consequences of that are. Yes he might tell her. Be prepared for that. I wouldn't withhold all his presents. Just some. Not for long either. At least a day. His reaction will show if there are indeed deeper issues going on.

Don’t use presents/Xmas as a bargaining chip - that’s not a decent, adult response. However, it sounds really tough because you suggest there are deeper issues, so I hope you are getting the support you need.

I wouldn't do this. Like you say it won't make any difference to his behaviour and will just cause upset for everyone.

You do need to nip this in the bud though. Do this or I'll ... could escalate to much more serious threats.

I'm not sure how you deal with the immediate behaviour - probably not by taking away Christmas presents but certainly by insisting on consequences not only for actually telling the 6 year old but also for attempting to threaten you. I would definitely want to tackle the fact that he's rude and aggressive. It can't just be negative consequences either. There's obviously a pattern of behaviour that's been established that needs to be broken. Has he begun to see himself as the black sheep? Could you get him onside with more responsibilities (and more freedom/rewards as a result)?

And give him his presents this isn't the time to correct hisbehaviour start afresh in the new year because if you don't give his Christmas then your other family members will have the shittiest of days.

I'd also consider family therapy if you can afford it. These family roles can become entrenched without you really noticing it and then are incredibly hard to break out of. There's no shame in seeking support.

You are being as bad as he is by doing this! It all sounds quite toxic.

I would do similar to what MakeItRain has suggested. Tell him the consequences of telling her and that you will not be bribed into not carrying them out. Then, if he does tell DD, just explain to her that of course Father Christmas will bring her presents on Christmas Eve and her brother is just trying to be mean.

I always said to mine that they can think what they like, but if they say out loud that a certain person isn't real they don't get stocking presents.
That worked when dd2 was desperate to give her knowledge to ds.

If you say you don't believe you naturally don't get as FC is not going to give to people who say he isn't real. It's a natural consequence.

My Mum told me that my Uncle did this, and got a stocking full of coal...

Obviously this threatening behaviour is not OK, and this little video isn’t an answer as such, but worth a look. Might be worth showing to your son as well?

Why not sit down and talk to him about the meaning of Christmas and the reason we tell children that Santa exists?
Tell him that whether Santa is real or not is irrelevant and that the magic of Christmas will exist whether he tells his sister the truth or not.

He's not stupid, he's old enough to understand.

Tell him if he wants a rubbish Christmas that's fine, but that the rest of the family will have a lovely time with or without him.

We have said we won't put up with his behaviour & if he did tell her he would not receive any Christmas presents.

So all you PPs are advocating she threatens a punishment then doesn't follow through?

I would do exactly what you have threatened and then explain to his sister why he isn't getting any presents - because everyone knows Santa only gives to good children and trying to spoil her Christmas is not good. He is 10, not 4 - the simple fact he is blackmailing you shows he knows exactly what he is doing.
Then in the new year get some help for you and him.

I have donned my hard hat as I will no doubt be vilified...

It's replacing his threat with one of your own. It is all very toxic.

It's so difficult actually. If you call his bluff and say "go ahead and tell her" and he does, it's not fair on her. She'll question why he got presents if he doesn't believe. But you can't just dismiss his behaviour either. I'd try a big word with him about how much this is upsetting you and ask if you can make a compromise over Christmas to try harder with behaviour and to stop all the threats.

Then after Christmas try therapy, maybe alternative routes to ones you have tried?

We have always taken the line that Santa works in collaboration with my partner and me.

So, if he really wants to tell his sister that Santa doesn't exist in the fairytale version of events, why not let him go ahead.

She'll find out sooner or later anyway.

It might be worth saying it would be kinder to let her believe the story for this one more Xmas.

But I don't think this should be quite such a big deal. Older siblings often find it frustrating to have to make allowances for younger ones.

I would. Some lessons need to be learnt the hard way and I would make it absolutely clear that it is HIS actions that will lead to those consequences.

He certainly would forgo his stocking in this house.

No don’t. It will have the opposite effect. You need different parenting tools. It sounds as if this started with the birth of your 6 yo. It also sounds as though he is angry and jealous of your 6 yo. This makes me wonder if you as parents didn’t manage the introduction of his sibling well. That would you, not him. In an ideal situation you would have some family therapy. Child psychologists are brilliant.

& if he did tell her he would not receive any Christmas presents.

Well, as you've said it, if he does you will have to follow through.

I wouldn't be giving into blackmail and I would be telling him that.

I would also be making sure I had some coal...

Depends how you FC though - does he bring all the presents or just the stocking and the rest are from people?

I have never really understood why adults make threats to children that they know that they cannot carry out. because children, very quickly realise this and know that any threats of consequences are just hollow. Why does he want to tell his sister? what is the point of doing it? so that she is upset and her Christmas is ruined. If that is the case then you do indeed have a very nasty young lad on your hands and as others have said its not going to be a quick fix. You really need to get a grip on his behaviour before puberty because this is only going to get worse and not better. We have always split christmas as santa presents in the stocking and big presents from the parents. If you to this in your family as well then I would tell him quite openly and clearly and in front of his younger sibling that as he doesnt believe in Santa any more then theres no point leaving out his stocking because santa wont fill it.

You cannot keep making empty threats with no consequences. either be prepared to follow them through in the least damaging to the rest of the family way or stop making them.