The university student who was killed in the tragic Titanic submarine 'implosion' was 'terrified' about the trip and only joined the crew to please his dad for Father's Day, his heartbroken aunt has revealed.

Pakistani businessman Shahzada Dawood and his son Suleman, 19, were two of the five victims killed instantly when the OceanGate submersible suffered a 'catastrophic implosion' just 1,600ft from the bow of the Titanic, according to the US Coast Guard.

The other victims were OceanGate CEO Stockton Rush, French Navy veteran Paul-Henri (PH) Nargeolet and British billionaire Hamish Harding. They had been missing since the Titan sub vanished on Sunday, prompting a nail-biting search for the crew.

Tragically, Azmeh Dawood - the older sister of Mr Dawood, the vice chairman of Engro Corporation - told NBC News that her nephew 'wasn't very up for it' but felt compelled to please his father, who was very passionate about the 1912 shipwreck.

'I am thinking of Suleman, who is 19, in there, just perhaps gasping for breath ... It's been crippling, to be honest,' she told the US outlet from her home in Amsterdam.