A family gathering ended in bloodshed when Christopher Ruby buried a flick-knife into the chest of his uncle, Shannon.
Frank and Ursula Ruby lost their son then -- and now their grandson to a six-year jail term.
Shannon's partner, Nora Harty, said:"Shannon will not be able to see his daughter [Ann] grow up.
"He had a heart of gold -- we will never get over the loss of Shannon," she added.
In an emotional plea for leniency, Frank and Ursula said that they consider Christopher to be far more than just a grandson.
"Christopher has lived with us for 12 years and we would class him as a son also," they said.
But the court warned their plea could not be acceded to given the serious nature of the case and the fact the young man had deliberately gone to get a knife and then followed his uncle to where the fatal assault occurred.