Ronan Sexton, a son of Neeson's sister Bernadette, was 35 years old. He died in Cushendall, a village in Northern Ireland, surrounded by family members.
During a night out with friends in Brighton, southern England, in 2014, Sexton climbed on top of a phone booth, lost his balance and fell head first to the ground. He was initially treated at a local hospital and later transferred to a neurological center.
Nearly 10 years ago, Neeson – the 66-year-old star of the "Taken" films – lost his actress wife Natasha Richardson after she died from a head injury suffered during a skiing accident in Canada. Richardson was 45 years old and the couple had been married about 15 years.
The Associated Press contributed to this story.