Azmeh Dawood, the aunt of Suleman Dawood, son of Pakistani businessman Shahzada Dawood, told NBC News Thursday that her nephew had expressed reluctance about joining the Titan submersible trip.

The 19-year-old university student accompanied his father on the expedition as it coincided with Father's Day weekend, aiming to please his dad.

According to Dawood, Suleman confided in a relative about his fear regarding the journey. 

He told the relative that he "wasn't very up for it" and felt "terrified" about the trip.

Following the announcement made by OceanGate, the company behind the Titan expedition, confirming that all passengers aboard were presumed dead, Azmeh said: "I feel disbelief."

Additionally, the family of the British-Pakistani father and son expressed "profound grief."

Shahzada Dawood and his son are members of the Dawood dynasty, owners of an industrial empire that is one of the most profitable in Pakistan.

"It is with profound grief that we announce the passing of Shahzada and Suleman Dawood," said a statement from the Dawood Foundation, a family-run education charity.

"We extend our heartfelt condolences to the families of the other passengers on the Titan submersible," it read, signed by Hussain and Kulsum Dawood, Shahzada's parents.

"We are truly grateful to all those involved in the rescue operations. Their untiring efforts were a source of strength for us during this time."

Hussain Dawood is one of Pakistan's richest men and head of the Engro Corporation which has an array of interests in energy, agriculture, petrochemicals and telecommunications.

In a statement, Engro said it was mourning Shahzada -- who served as vice-chairman -- and "his beloved son" Suleman "with heavy hearts and great sadness."

"We extend our heartfelt condolences to the family, colleagues, friends, and all those around the world who grieve this unthinkable loss."

Also Read: Lost submarine imploded, passengers killed

Earlier, debris was discovered on the ocean floor suggesting the missing submersible near the wreck of the Titanic suffered a "catastrophic loss" of pressure, the US Coast Guard said Thursday.

"Upon this determination, we immediately notified the families," Rear Admiral John Mauger told reporters in Boston.

"On behalf of the United States Coast Guard and the entire unified command, I offer my deepest condolences to the families."

The 21-foot (6.5-meter) craft, operated by OceanGate Expeditions, began its descent on Sunday but lost contact with the surface less than two hours later, according to authorities.