A dispute over the validity of legal documents signed by an 88-year-old Shanghai resident, to leave his property to his local greengrocer when he passes away instead of his relatives, has continued with more details surfacing.

Ma Lin, the man in question, lives alone in Shanghai's Baoshan district. With his wife and son passing away years ago, Ma befriended his local greengrocer who in turn has helped Ma in his daily life and when he needed more urgent help.

Ma fell at home in 2017. The greengrocer took him to the hospital and continued to care for him during his recovery, according to China National Radio. When Ma was discharged he invited the greengrocer and his wife and three children to move in with him.

In 2019, Ma had two legal documents drawn up. One appointed the greengrocer as his legal guardian, and the other details his desire to bequeath his property, an apartment currently valued at 3 million yuan ($457,000), to the greengrocer.

The legacy-support agreement requires the greengrocer to support Ma during his lifetime and places him in charge of his internment after death, in return for Ma's estate.

Both documents were notarized by the notary office in Shanghai's Putuo district.

The greengrocer told Xinmin Evening News that he has taken care of Ma for the past 10 years, and feels at ease with Ma's decision to bequeath his property to him.

However, Ma's relatives, upon hearing about the documents, have challenged their validity.

Ma's niece, surnamed Wu, told Beijing News that some relatives also cared for him during his hospitalization in 2017. Another relative added that they took turns taking care of Ma while he was in hospital and hired caregivers, opposing other accounts.

Wu said that after being discharged from the hospital, Ma refused offers from the relatives to provide care.

Additionally, Ma was diagnosed with the Alzheimer's disease in 2017, and his relatives say this draws into question the validity of the legal documents.

In response, Zhou Xianchun, from the notary office in Putuo district made an announcement on Thursday, saying "The notary has talked with Ma many times and he repeatedly confirmed his wishes before the issuance of the notarization."

The conversations with Ma and his medical records didn't show any signs to prove he was unable to make good judgment, he added.

Zhou said it had checked Ma's situation with his neighborhood committee during several phone calls.

"The relatives with doubts can submit an application for a review to the office within a year," he said.

An Xiang, director of Beijing Dexiang Law Firm, said those with doubts should provide evidence to prove that Ma was in a state of incapacity or limited capacity before the notarization.

Official data shows that the elderly population in China, those aged over 65, is expected to reach 248 million this year.

"In an aging society, there will be surging demands and cases in this area and the law will progress continuously," he said.

Zhu Wei, an associate professor at China University of Political Science and Law, said the effectiveness of appointing non-relatives as guardians lies in supervising whether those appointed perform their duties.

"It's crucial for local authorities to visit the family regularly to supervise the beneficiary's performance," Zhu said.