Legal Question in Criminal Law in California

That will depend on the circumstances. If it's reasonable for your family to be in fear due to these posts -- and if they actually are in fear -- then the author can be arrested. The fact that he says these posts are just jokes doesn't mean they really are, or that your family has to believe they are.

The authorities will consider the disclaimer when deciding what seems reasonable under the circumstances. That's because the circumstances include the entire content of the posts. But it will not prevent an arrest. Depending on what the posts say and what else is going on, the disclaimer might not count for much at all.

Good luck.