Five years ago Sean Edley died after suffering an epileptic attack – a condition he developed after an unprovoked street attack.
He was assaulted on Westgate in Wakefield while walking home during the early hours of January 28, 2007.
A man pulled up in a silver Ford Focus, close to Westgate Railway Station, and punched him to the ground before driving off.
Mr Edley, who was born in Dewsbury and went to Earlsheaton High School, was left with a fractured skull and bleed on the brain after the vicious beating.
Later he developed epilepsy – a condition a coroner said caused his death when he suffered a massive fit on November 2 2010, aged 41.
And as his family marked the fifth year since his death, they said they will never give up their fight for justice.
Mr Edley’s sister, Joanne Jackson, of Ossett, said: “This cowardly person who did this never came forward but they must know what they did.
“It has been really hard for us because we know Sean did not deserve it.”
Mr Edley, of Lupset, Wakefield, was described as a caring and loving man, who enjoyed spending time with his family and going to gigs.
But his life dramatically changed after the brutal attack.
His mum Winn, 70, of Liversedge, said: “Sean had lots of friends and everyone knew him. He was a really lovely lad.
“I can’t understand why anyone would be so aggressive towards him. I just want to know why. The impact of the punch changed his life. He could not go out and socialise like he used to.
“It was upsetting because he was never like that before.
“It is important for us to keep what happened to Sean in the spotlight because we do not want him to be forgotten.”