Shahzada Dawood's sister said she is "absolutely heartbroken" by the news of the submarine's implosion.
Suleman Dawood, the son of Pakistani billionaire and among the five people who died after a "catastrophic implosion" of the Titan submersible, was terrified of the daring expedition, his aunt has said. Speaking to NBC News, the older sister of Pakistani businessman Shahzada Dawood said she is "absolutely heartbroken". He joined the expedition because it was important to his Titanic-obsessed father. The US Coast Guard said the debris of the submersible was found 1,600 feet (488 metres) from the bow of the Titanic.
"I feel very bad that the whole world has had to go through so much trauma, so much suspense," Shahzada Dawood's sister Azmeh said in a phone interview to NBC News.
"I feel like I've been caught in a really bad film, with a countdown, but you didn't know what you're counting down to. I personally have found it kind of difficult to breathe thinking of them," she added.
Ms Dawood said that she wouldn't have gotten into the Titan "for a million dollars".
He remarks came after the sombre announcement by US Coast Guard, which ended a multinational search-and-rescue operation that captivated the world since the tiny tourist craft went missing in the North Atlantic four days ago.
"On behalf of the United States Coast Guard and the entire unified command, I offer my deepest condolences to the families," Rear Admiral John Mauger told reporters in Boston.
Along With Mr Dawood and his son, British explorer Hamish Harding, French submarine expert Paul-Henri Nargeolet, and Stockton Rush, CEO of the sub's operator OceanGate Expeditions were also on board.
"These men were true explorers who shared a distinct spirit of adventure, and a deep passion for exploring and protecting the world's oceans," OceanGate said in a statement.
OceanGate Expeditions charged $250,000 for a seat on the sub. In a 2018 lawsuit, its former director of marine operations raised concerns about the "experimental and untested design" of Titan.