Hey, Quaere. It is nice to see you back and posting here!
innocentdragon, I know very little about probate law, but I have a few questions about your situation.
What roles in this probate case do you and your relative play? Are either of you petitioning the court, or have either of you petitioned the court, to become administrator of (what I assume is) your mother's estate? Is this where the dispute is arising? Against whom did the court impose the constructive trust?
Generally, to my knowledge (which admittedly is limited), if you have any objections to any petition filed, you would call the probate examiner's office to make your objection known. A hearing will be scheduled to address your objections and it is in this hearing where you would dispute the false and potentially defamatory statements that have been made.
With that said, what Captian Picard and Quaere said about statements made in the course of or in reference to a court proceeding, by any actor in the case, is true. These statements, even if false and defamatory, are considered "absolutely privileged" and would be protected from any defamation action. This is to allow for free and unfettered speech in the courtroom. The time to address any lies that are told is in the courtroom, with your own supporting evidence and testimony.
If your relative is not limiting his false and potentially defamatory comments to court papers and proceedings, however, and is communicating to others outside this protected realm any falsities that are reputationally injurious, then there is a chance that the defamatory statements could be legally challenged. For this, however, you would need to consult with an attorney in your area, for a review of all of the facts.
Edit to add a (perhaps unimportant) note: Captian Picard and Captain Picard appear to be two different members on this forum.
