Cormac Roth, the son of actor Tim Roth (61, "Pulp Fiction", "The Planet of the Apes"), died of cancer at the age of 25.
They lost their "beautiful boy" after a "valiant battle with cancer," the family said on Monday.
According to the announcement, Cormac had already died on October 16.
The young musician was "extraordinarily talented" and full of "wild and contagious" energy.
He had attended college in the American state of Vermont.
Cormac was from the actor's 1993 marriage to fashion designer Nikki Butler.
The couple have another son together.
Cormac announced the diagnosis on Instagram in June.
The rare type of cancer was found in November 2021.
Since then he has lost half his hearing and a lot of weight, the musician wrote.
He fights against it with all conceivable treatments, including chemotherapy, surgery and transfusions.
"Life is short," he addressed his followers.
"Do all the things you love."