Family Questions Man's Alleged Drowning During Underwater Proposal: 'All We Keep Talking About'

The sister of the Louisiana man who died while proposing to his girlfriend underwater is still grappling with her brother’s cause of death, as she says he was a strong swimmer with experience snorkeling.

Mandy Hoffman told the Associated Press that the death of Steven Weber Jr., who popped the question on vacation by swimming down more than 30 feet to the window of his underwater hotel room on Thursday, has left their family with many unanswered questions as they wait to hear more from authorities in Tanzania.

Hoffman said authorities in the country informed her via email that an autopsy had been conducted, but did not immediately identify a cause of death.

She added that her family is questioning the circumstances surrounding Weber’s death at age 40, as he was a “strong” swimmer who had been snorkeling multiple times, the AP reported.

“This is all we keep talking about,” she told the outlet. “Something other happened besides him running out of breath.”

A State Department official confirmed the death of a U.S. citizen in Tanzania to PEOPLE, but declined further comment.

Spokespersons for the Manta Resort, where Weber was staying, and the U.S. Embassy in Tanzania did not immediately return PEOPLE’s request for comment.

Weber was vacationing with his girlfriend, Kenesha Antoine, when he proposed with a handwritten note and a ring box outside the window of the couple’s underwater hotel room.

Hoffman told the AP that after Antoine excitedly accepted Weber’s proposal, she headed to the deck level of the room to meet him, but he never surfaced.

Though she tried to get help, Antoine was unable to contact resort personnel by phone or by radio, and eventually had to flag down a passing boater to help find Weber, Hoffman told the AP.

“[The boaters] brought him up to the surface, and they performed CPR,” Hoffman told local CBS affiliate KSLA. “He had a slight pulse whenever they brought him, but they tried to do CPR and they just couldn’t bring him back.”

RELATED: ‘Loss’ of Man Who Died During Underwater Proposal to Girlfriend Is ‘Unbearable’

Weber and Antoine had been dating for two years after meeting through a mutual friend, and were in Africa as part of a birthday trip for Antoine, Hoffman told KSLA and the AP.

“He’s a romantic. And I know in his mind, this was the best way to do this so that Kenesha could have this memory forever,” she told KSLA. “And I hate that this is the memory that she’s going to have … She’s part of our family now and I don’t ever want her to feel alone.”

Antoine mourned her loss in an emotional Facebook post shortly after the tragedy, in which she shared video of Weber’s proposal and her giddy acceptance.

In the clip, Weber swims up to their room’s window and unfurls a handwritten declaration of love (kept dry in a plastic bag) before opening a ring box.

“I can’t hold my breath long enough to tell you everything I love about you BUT…everything I love about you I love more every day!” the note read. “Will you please be my WIFE? Marry Me???”

In Antoine’s post, she wrote that though Weber never got to hear her answer, she accepted wholeheartedly.

RELATED: Louisiana Man Drowns After Proposing to Girlfriend Underwater: ‘You Never Got to Hear My Answer’

“We never got to embrace and celebrate the beginning of the rest of our lives together, as the best day of our lives turned into the worst, in the cruelest twist of fate imaginable,” she wrote. ”I will try to take solace in the fact that we enjoyed the most amazing bucket list experiences these past few days, and that we both were so happy and absolutely giddy with excitement in our final moments together.”

Neither Hoffman nor Antoine immediately returned PEOPLE’s request for comment.

The CEO of the Manta Resort confirmed Weber’s death in a statement, and said he was free diving alone when he drowned.

“Our sincerest condolences, thoughts and prayers are with his girlfriend, families and friends impacted by this tragic accident,” Matthew Saus said in a statement to PEOPLE. “A male guest tragically drowned while free diving alone outside the underwater room. The weather and water conditions were calm. The underwater room lies approx. 300 meters offshore. The depth of the water around the underwater room is 10 meters.”

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Meanwhile, Hoffman, along with the Zachary High School Class of 1997, organized a GoFundMe page to help cover his return and burial expenses, which has so far raised more than $17,000.

The family said in a statement: “We lost this beautiful soul on Thursday, September 19, 2019. He was with the love of his life, doing what he loved in life – adventure. Words cannot express the void that now exists in the hearts of everyone he loved and who loved him. His beautiful eyes and infectious smile will stay with us forever.”