Michael Hickey, 31, was speaking after he and his cousin Vincent, 31, were released from jail to go to the funeral of Michael's father, Joe, in Birmingham.
The two men were convicted with James Robinson, 56, and Patrick Molloy - who died in prison in 1981 - after 13-year-old Carl was shot in the head in 1978. The boy had gone to Yew Tree Farm, Stourbridge, West Midlands, and apparently disturbed burglars.
The Home Office has been considering for a month whether the case should go back to the Court of Appeal following an investigation by Merseyside detectives.
The men's solicitor, James Nichol said he was disappointed the process was taking so long: 'If there is a miscarriage of justice then it is now being extended by the year and three months since I submitted a petition to the Home Secretary.'