When an older sibling knows the Santa secret
The older child can still enjoy Christmas without being made responsible for a younger sibling’s belief.
Talk to the older child privately, before the rush of Christmas Eve. Ask how they want to take part this year. They may like wrapping a small present or writing a clue; they may not want any role in the Santa story. Either answer is allowed.
Make the agreement small
Instead of “Don’t ruin Christmas,” try “Your brother is still enjoying the story. If he asks you, you can send him to us.” This protects the sibling relationship without asking the older child to invent lies. Tell visiting adults the same plan so they do not make the child perform on demand.
They can choose the Christmas movie or help set the table without taking charge of anyone else’s belief. If the younger child asks a direct question, an adult can answer it. And if the secret slips, respond to the question rather than blaming the older child.