Citizens of the state of Missouri who meet the criteria established by the United States Department of Veterans’ Affairs, or its successor organization, for veteran status or who have an honorable discharge from the National Guard, with preference given to the Missouri National Guard, and who require institutional health care services shall be entitled to admission into a Missouri veterans’ home. No spouse of a qualified veteran shall be required to vacate the premises of a Missouri veterans’ home if the spouse was a resident of the home on August 28, 1989.