I could not find Hillard in the Social Security Death index; he may have still been living in 1993. (Interestingly, of the 8 Hillard Halls in the index, 3 were born before 1910 with numbers issued in KY, 2 in Letcher Co. and 1 in Knott Co. It must be an eastern Kentucky name.)

There are two good possibilities to be this Ruby Hall in the SS death index:

442-28-4917 b. 17 Oct 1909 d. Jan 1978 Westville, Adair Co., OK
443-34-0475 b. 6 Oct 1911 d. 31 Jan 1989 Oklahoma City, OK