What happened to George Wilson in the show Dennis the Menace when he didn't come back?

The character of Mr. George Wilson , who was played by the late Joseph S. Kearns (February 12, 1907 - February 17, 1962) , was replaced by Gale Gordon (February 20, 1906 - June 30, 1995) when J.S. Kearns died February 17, 1962 from a cerebral hemorrhage .