The article is unclear on that. First is says, "Laffoon also reportedly expects to receive another $400,000 annually from royalties and residuals." Then it says, “the probable value of the annual income from all the estate’s property is approximately $400,000.” Those are not the same thing. $400,000 could be the present value of the projected income stream, which could be only a few thousand dollars a month depending on how many years they expect the income to come in (e.g., $4,000 to $5,000 per month for the next ten years would have a present value of approx. $400,000, depending on the interest rate used).
Since the royalty income is from a memoir that she wrote but that has not yet been published, any number they used is probably an optimistic guess.
Take the money and move to Wyoming. Get a nice house for far less than $400k and live comfortably on The residuals.