I have a 12 year old son who will not be touching this game. Some of the content is too dark for children, and lets not get started on the decaps. Games have rating systems for a reason.
I assure you children are exposed to far worse every day, through television, music, their friends ... If I were you, I wouldn't worry too much about your son playing Skyrim, because chances are he's already seen a decapitation and whatever else it is you're afraid of him seeing.
But he's your child, and you get to raise him as you please, and you won't hear me say otherwise.