Court documents in the US claim Roger Curry was brought from his home in LA to Britain and left in a car park by his wife and son.
The explosive claims are part of an investigation by the BBC1 programme Panorama, being screened tonight.
The 76-year-old was found at a Hereford bus station without ID.
It is alleged that two men were with him when he was found – a passerby and a younger man with an American accent who paramedics say fled the scene when they arrived after being alerted by concerned citizens.
The Daily Mail reports that he told the staff at the hospital that he was not from the area but he thought he had been training nearby. He appeared well cared for and was wearing brand new clothes.
Mr Curry spent eight months in a nursing home while authorities tried to work out who he was.
He remembered his name but little else – after an appeal to the public, police traced his identity back to his family home in LA.
He is now under the care of health authorities in LA. His family deny they knowingly left him behind in the UK.
Because of the high cost of care in America, elderly people are sometimes abandoned at hospitals in a practice called granny-dumping.
