Wednesday marks five years to the day American aid worker Alan Gross has been locked up in a Cuban military prison on charges of espionage, and his family and U.S. officials are urging the Cuban government to release the ailing prisoner.

Gross' health is said to be failing, with his eyesight gone in one eye and a hip injury that's left him barely able to walk, ABC News reported. The 65-year-old has also lost several teeth and over 100 pounds since Cuba sentenced him in 2011 to 15 years in prison for allegedly trying to help the U.S. overthrow the Cuban government.

Judy Gross, the prisoner's wife, released a statement pleading for President Barack Obama to coordinate his release before he dies.

"Enough is enough. My husband has paid a terrible price for serving his country and community," his wife said according to ABC News.

"After five years of literally wasting away, Alan is done," Judy Gross continues. "It is time for President Obama to bring Alan back to the United States now; otherwise it will be too late."

Gross, a former USAID subcontractor, has vowed to go on a hunger strike if he is not freed, saying he would rather die than spend another year in prison. He has stopped accepting food and visits from the Havana-based U.S. Interest Section, ABC News reported. He's also refused medical attention and care for his teeth from the prison's hospital.

The U.S., which has a longstanding embargo against Cuba, called on the Caribbean island nation to release Gross.

"The Cuban government's release of Alan on humanitarian grounds would remove an impediment to more constructive relations between the United States and Cuba," the U.S. State Department said according to Reuters.

Cuba has offered to release Gross in exchange for the release of three Cuban spies the U.S. arrested in Florida for infiltrating anti-Castro groups, Reuters reported. The U.S. has turned down the offer.