Max Heard died in his bed in December 2016, half a year before the death of his father in a hotel room on Friday.
The 22-year-old 'died peacefully in his sleep', according to an obituary written by his mother Sharon, and 'was in deep grief of not having a father participating in his life.'
John and Sharon Heard also shared a daughter, Annika.
John and Melissa Leo, who were in a previous relationship together, has a son and named him John Matthew Heard.
The 72-year-old was found dead by a maid in a hotel in California on Friday, according to family sources.
The star played the father of Macaulay Culkin’s character Kevin in the hit 1990s films.
Heard also starred in Big with Tom Hanks, Gladiator and The Pelican Brief, while TV work included roles in Battlestar Galactica and The Sopranos.
His death is not being treated as suspicious.