The Chinese military surgeon who exposed the government’s cover-up of the the severe acute respiratory syndrome (Sars) epidemic in 2003 has been under de facto house arrest since last year, according to his friends and family.

The fate of 88-year-old Dr Jiang Yanyong, a retired general in the People’s Liberation Army, has been brought into the spotlight after a whistleblower doctor, Li Wenliang, who exposed the coronavirus epidemic, died last Friday at the age of 34.

Since April last year, officials have cut off Jiang’s contact with the outside world and restricted his movements after he wrote to the top leadership asking for a reassessment of the 1989 Tiananmen Square pro-democracy movement, said a close friend, on condition of anonymity.

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His wife, Hua Zhongwei, confirmed he was confined to his home. “He is not allowed to be in contact with people outside. He is at home. He has no means of communication [with outside],” she said. “His health is not good. He is not in a good mental state either. He is not very well.”

She said he suffered from pneumonia and was treated in hospital last year. “I am sorry, it is not convenient to say more,” she said.

Jiang was treated in 301 military hospital in Beijing – the hospital where he served for more than 60 years – from April last year for more than a month, and was heavily guarded and banned from being visited by his family, his friend said. The doctor became agitated and was given medication, which led to severe memory loss, the friend said. Officias have restricted his movement since then.

Another friend added: “We haven’t seen him for a long time and can’t contact him. We heard his brain has been severely affected.”

Jiang has pleaded more than once with the authorities to reappraise the Tiananmen pro-democracy movement, which was brutally suppressed 31 years ago. It remains one of the most politically sensitive issues in China.

Jiang became a national hero by exposing the government’s cover-up of the Sars epidemic in 2003, but was detained and forced to undergo “brainwashing sessions” after he called on the government to acknowledge that the 1989 student movement was a “patriotic movement”.

Facebook Twitter Pinterest A newspaper stall features Jiang Yanyong on the cover of a magazine in 2003, when he exposed the cover-up of the Sars crisis. Photograph: Guang Niu/Reuters

“Errors committed by our party should be resolved by the party. The sooner this is done and the more thoroughly this is done, the better,” Jiang wrote in 2004, the 15th anniversary of the military crackdown.

In a 2013 interview with Southern People Weekly, an outspoken state magazine, Jiang stressed his insistence on speaking the truth. “As a doctor, protecting patients’ health and lives is first and foremost … the most basic requirement for a doctor is to speak the truth. I have experienced numerous political movements for 50 years, I feel deeply that it is easy to lie, so I insist on never telling lies,” he told the magazine.