Marvin Couson, 39, was on an evening out with his cousin and a friend when they were caught in crossfire at a bar in Shoreditch, East London, in May 2002.
He was hit by a bullet in the chest and left in a vegetative state for more than a decade from a brain injury caused by the shooting.
Mr Couson’s sisters Margaret and Deborah appealed for anyone with information about the gunmen to come forward as a murder investigation was launched.
“Marvin’s suffering has now ended, but ours has only begun,” they said.
“We have visited him every single day and he was not alone when he passed away.
“We want people to look at the picture of Marvin suffering and realise this is real.
“By staying silent and not helping police you have allowed the murderer to walk free.
“The person who pulled the trigger needs to be caught and we need justice for Marvin.”
Police were called to Lime in London Bar, or Lime Bar, in Curtain Road at 3.40am on May 12, 2002, after reports gunshots had been fired.
Mr Couson, aged 26 at the time, of West Norwood, was found lying on the ground with a bullet wound to his chest.
He was taken to the Royal London Hospital with critical injuries to his heart and other internal organs before being transferred to the Royal Hospital for neuro-disability.