Asked by user in Montana. Answered by Enjuris Editors.
There is a personal injury cause of action when someone wrongly ruins your reputation by spreading false information, which is called "defamation of character."
The elements of defamation are that a statement was made and published (a Facebook post would likely count as publication), the statement was false, and the defamed person suffers injury as a result.
Breaking it down, it doesn't seem to be in question that a statement was made and published. It would seem as though the statement is false because obviously if she is saying that the child is deceased when he is, in fact, alive, then the statement is untrue. If she is also claiming abuse and you can prove that is untrue, then this element would also hold up.
Montana defamation laws are a little different from most states. In many states, a person's opinion is not considered defamation unless it contains a false statement of fact. In this case, the fact that your son is alive would mean that the grandmother was incorrect, even if she truly believes he is deceased.
The part that could be challenging to prove is how you were injured. You would have to show either financial loss that happened directly as a result of her statement (for instance, you lost your job or earning capacity, or you lost business as a result of the damage to your reputation) OR pain and suffering or emotional distress because of your personal humiliation or loss of standing in your community.
Ultimately, it sounds like while the person might have done you wrong by saying things online that were false and damaging, it could be difficult to prove your injuries. Your best "defense" could be that your son is alive and well (and I hope he recovers quickly) and you can prove her wrong.
However, if you believe that her statements cost you business or caused you to suffer other losses, you can certainly contact a personal injury attorney for additional guidance.