Chike Butcher is an unseen character, he has never appeared on screen. Although he is seen in a photo and died before 1988.
"Chike" Butcher was born in about 1910 in London. He worked for the London Transport and married to Mo Butcher in about 1936 and they had two children, Joan born about 1938 and Frank born 27 March 1940. He gained the nickname Chike. His real first name has never been revealed in the show, to any knowledge.
According to the "EastEnders Handbook" by Hilary Kingsley in 1991, Chike was indeed his nickname. In an episode broadcast in 1999 or 2000, Peggy is looking at her marriage certificate to Frank. If that episode can be tracked down, it may give Frank's dad's real first name.