Claims by a division mental health facility against the estates of deceased consumers may be presented to the executor or Administrator in the manner required by law, and shall be paid as preferred claims equal to claims for expenses of last illness. When a deceased person has been maintained at a division mental health facility at a rate less than the maximum usually charged, or the facility has incurred other expenses for the benefit of the person for which full payment has not been made, the estate of the person shall be liable if the estate is discovered within 5 years after the person’s death.