Drew Principe, 17, said he came up with the idea for a fundraiser after meeting Henry Oster during a school assembly in January.
Oster told students at Viewpoint High near Los Angeles about his experiences during World War II.
In 1941 he and his family were deported by Nazis from their home in Cologne, Germany, a few weeks before he was supposed to celebrate his bar mitzvah, usually held at 13. They were taken to a ghetto in Poland before he was taken to the Auschwitz concentration camp. He was sent to a few different camps before being liberated at 17 and eventually moving to Los Angeles to become an optometrist.
Principe discovered that Oster had never been to Israel, so the teen decided on the spot to give the man a bracelet he had bought on a trip to the Holy Land a few years ago. The bracelet has the Shema, a Jewish prayer, inscribed on it.
"It really is a gesture that cannot be measured," Oster told the Ventura County Star about the gift. "I don't wear jewelry, but I have not taken this off except for the shower."
Principe and Oster began a "life-changing" friendship, the teen told the newspaper.
An online fundraiser took off and quickly raised close to $15,000.
Oster and his wife along with Principe and his family left on Monday for Israel, where Oster will meet his cousin and be formally recognized by the Israeli Holocaust memorial as a survivor.
He will also celebrate the bar mitzvah he never had.
Ultimately, Oster said, he decided to accept the offer and have the ceremony in memory of those who died and will never have the chance to experience the ceremony.
"I decided to honor my father and my parents and ... the desecrated Torah and all the victims who never had a chance," Oster said.