Seema Khan, Shaikh's cousin, told Al Jazeera: "He has been assessed in the UK as suffering from bipolar disorder. And the evidence shows that he is displaying the symptoms of this disease.
|Shaikh was arrested in 2007 after he was found to be carrying four kilos of heroin [AFP]
"We lost touch with him about six years ago when he left for Poland. We know that he was picked up from Poland, living rough on the streets, by a gang.
"[They] must have offered him food and a bed, and duped him and used him as a mule.
"He did not actually go out to obtain drugs, the drugs were brought to him ... He would not have had the money to get on a plane to China."
Shaikh's family has said that the gang offered him a music recording contract to tempt him to fly to China.
A court in China rejected Shaikh's final appeal on December 21. He would be the first European citizen to be put to death in China since 1951 if executed.
"The case has been processed in accordance with the law ... The defendant's litigation rights and legitimate treatment have been fully granted," Jiang Yu, a Chinese foreign ministry spokeswoman, said last week.
Gordon Brown, the UK prime minister, has had his request for a pardon rejected by Beijing.
A vigil has been held outside the Chinese embassy in London for Shaikh.
Al Jazeera's Beijing correspondent Melissa Chan said Chinese authorities take the issue of drugs very seriously and a last minute stay of execution was not likely.
She added it was not clear how Shaikh would be executed.
Until recently most executions in China were carried out using a pistol shot in the back of the neck, but several provinces have started to introduce lethal injection.