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A Washington man who died of a rare form of cancer would still be alive today, his family says, had they not fallen victim to a hoax perpetrated by a stranger who promised to send $250,000 to help cover his medical bills.

Thomas Doty, who recently celebrated his 20th birthday, died on Dec. 19 after a three-year battle with osteosarcoma, a bone cancer.

"I honestly 100 percent believe my son would be here if that time had not been wasted," his mother, Tiffany Doty, told ABC New affiliate KOMO-TV in Seattle.

Earlier this year, family friend Johnathan Hillstrand, who is the star of the show "Deadliest Catch," stepped in and made a video. Soon after, the Doty family heard from a generous benefactor who said she was a nurse from Indiana.

Doty said she felt the stranger was "an answer to our prayers," she wrote in a Dec. 7 post on HealThomas.com, recounting the experience. She put the family's fundraising efforts on hold and began making arrangements to get her son to San Diego for costly, but potentially life-saving alternative treatments.

Every day the check went undelivered, precious time in Thomas' fight was lost, Doty said.

The family was met with a barrage of excuses.

"They came in the form of emails, forged Ally Bank statements, certified cashier's checks produced and altered by [the woman] herself, while trying to prove she had sent the $250,000, and countless forms of communications via phone calls, texts, and emails telling us the 'Check was in the mail' and that she would even cover the costs to save our home from the looming foreclosure with Chase Bank," Doty wrote.

After eight weeks of back and forth, it became apparent the strangers' promise was empty. The community rallied around Thomas, helping to raise money to send him to San Diego for treatment.

Despite improvements, the lost time took a toll on the young man, his mother said. He died on Dec. 19.

"She went to great lengths and just broke Thomas' spirit," Doty told KOMO. "Like he needed something … one more disappointment in his life."

Hillestrand tweeted the news of Thomas' death and thanked everyone who had helped.

"Thomas doty was pure in heart and good!" he wrote. "People like you restore my faith in humanity. I Will miss you my friend."