The man overboard from Wonder of the Seas was a teen vacationing friends, his sister says. She's worried authorities will stop searching for him.

• The person who went overboard on the largest cruise ship in the world is a teen traveling with his friends.
• Sigmund Ropich, 19, went overboard off Royal Caribbean's Wonder of the Seas this week, his sister said.

The passenger who this week went overboard from the largest cruise ship in the world — Royal Caribbean's Wonder of the Seas — is a 19-year-old college student who was vacationing with his friends, his sister told Insider.

Savannah Ropich described her sibling, Sigmund Ropich, as a hard-working "really great kid" in an email to Insider on Friday and said that her family is worried that authorities will soon stop searching entirely for the teen.

Sigmund went overboard from the 230,000-ton cruise ship on Tuesday night as the vessel — which departed from Port Canaveral, Florida — was off the coast of Cuba.

"The ship's crew immediately launched a search and rescue operation and is working closely with local authorities," a spokesperson for Royal Caribbean previously told Insider in a statement.

The rep said the cruise line had been working with the US Coast Guard, but the agency told Insider it was not involved in the case and said the Cuban Border Guard is responsible for coordinating the operation because the incident happened in Cuban territorial seas.

As of yet, there's been no sign of Sigmund, according to his family.

"We were told by the Cuban officials that they are done searching in the ocean. They are continuing only on the coast and land. I have a strong feeling they're going to end this search," Savannah told Insider.

Savannah said her family has been "praying hourly day and night" for Sigmund to be found.

"We are very hopeful if they open [the] search back in the ocean," Savannah said. "We need them to open it again."

Savannah said that Royal Caribbean didn't tell the family how long the ship's crew searched for her brother.

"I ask that they take matters like this seriously," Savannah said in an email. "Install man overboard systems, respond ASAP when someone is yelling 'Oscar, Oscar, Oscar' Be CLEAR when communicating WHO is searching for our boy."

Royal Caribbean did not immediately respond to Insider's request for comment on Friday.

Savannah said Sigmund had been in college, got "good grades," never got in "trouble," and loved to hang out with his friends.

His pals aboard the Wonder of the Seas are "grieving," she said.

The ship was two days into its seven-day sail when the tragic incident occurred.

"He was on the ship for vacation," Savannah said of Sigmund, explaining that he's "known for being a kind, reserved, humble kid. Always cool, calm, and collected."