Santa

Over the last several years I have threatened my two older children with no presents for Christmas if they told their younger brother the truth about Santa.  Out of all the warnings and threats I've given them this seems to be the only one they have heeded.  He's 11 now, in 6th grade, and should know the truth.  It could be embarrassing for him -- I'm assuming the others in his class have figured out the truth.  This would have been much easier when he was in 3rd grade.  I'm hoping he's just pretending and I won't be breaking his heart.