Aibu joint birthday party gift

[WeepingAngelInTheTardis]

Dc has been invited to his friends party, all good expect its a joint party with their younger sibling. Dc isn’t friends with the younger sibling.
Would I be unreasonable to get both a card but only give his friend money in their card? I was thinking £10 or would it be unfair to their sibling?

No, I think that’s what would be expected.

I think it’s fine to just take a present for one child

its fine to just take gifts for the child you know. My Dc went to a shared party and we just bought for the child in her class not his older brother

Yes giving a gift to your childs friend is fine .