If you don't name him, you certainly won't have anything to worry about legally.
Even if you did name him, you'd be pretty safe if you could back up what you say. Libel suits are often avoided when the allegedly libeled person is afraid of what might come out in court, and the fact that a suit could bring more attention to the charges, not less.
Plus, if he is deceased, exactly who would come after you?
And you are correct that titles cannot be copyrighted, except for trademarked names.
Even if you did name him, you'd be pretty safe if you could back up what you say. Libel suits are often avoided when the allegedly libeled person is afraid of what might come out in court, and the fact that a suit could bring more attention to the charges, not less.
Plus, if he is deceased, exactly who would come after you?
And you are correct that titles cannot be copyrighted, except for trademarked names.