Jack Doyle, 17, was stabbed through the heart during a party in Greenock in January 2012.
His father, Elaine's brother John, has tattoos on either side of his neck, in memory of his son and sister.
Steven McIntyre was convicted of murdering Jack when a jury rejected his claim that he had been acting in self defence.
McIntyre, then 19, was ordered to serve at least 15 years of a life sentence before he could ask the parole board to free him.
Jack's shattered grandfather - and Elaine's dad - died three days after the 17-year-old was stabbed to death.