The New York Post says the children's court-appointed lawyer recently interviewed the actor's accountant, David Friedman.
In a July 18 filing in Manhattan Surrogate Court, Mr Friedman recalled conversations with Hoffman where the topic of a trust for his children was raised. He said Hoffman wanted his estimated 35 million US dollars (£20m) fortune to go his longtime partner and the children's mother, Mimi O'Donnell.
According to the filing, Mr Friedman said Hoffman treated Ms O'Donnell "in the same manner as if she were a spouse".
The court-appointed attorney says the actor's will should be approved by the court because there isn't anything suspicious about it.