Kenneth's birth certificate shows his name as Kenneth Joe. There's no father's name. Mother's name is shown as "Maud Kate King late Minter formerly Mallett now the wife of Joe Cummings Cook East Kents Cyclists Brigade a builders scaffolder". The informant was Maud Kate Cummings of 16 New Street, Woodbridge.
There's no indication that Maud Kate ever married a Joe Cummings. Kenneth appeared in the 1921 census as Kenneth Joe Cummings King. I can't find him in the 1939 Register. His death, as Kenneth Joe King born 13 Nov 1918 was registered in Jan 1997 in Ipswich RD.