The defendant Patrick Joseph Weston is accused of holding a broom handle to the throat of David Devilliers while an unknown accomplice searched the Broseley property for cash during the incident in 2015.
Prosecuting barrister Mr Tariq Shakoor said that the case also related to fraudulent transactions linked to two bank cards belonging to the victim, who has the condition bi-polar affected disorder.
Mr Shakoor said: “Mr Devilliers lived alone and on Tuesday December 1, 2015 at about 11.30pm he was at home in his living room sitting in his armchair and fell asleep.
"He was awoken by the sound of of loud knocking on his front door.
“He went to answer and was confronted by two people. Both of them were wearing balaclavas.
“He didn’t see the face of either of these two people. Both were believed to be males.
“One of them pushed him into the hallway, they stumbled and fell onto the floor. He describes being on the floor while this robber sat on his chest and held him down.
"He describes getting a hold and a feel of this person who was on top of him. That robber picked up a broom that was leaning against the wall and and placed the handle across Mr Devilliers' throat.
“The second robber began a search of this property.
“It is plain that the robbers believed that there was cash to be found.
“The victim’s account is that he recognised the body shape of the robber who was restraining him. It was a large man, a man he had given money, a man who had actually lived under his roof, a man he had helped in his time of need. It was this defendant.
“It wasn’t just his shape that he recognised, but his smell and odour.”
Mr Shakoor told the jury that the victim pleaded with Weston, 36, “shouting out 'Paddy what are you doing? Why are you doing this?'”, but got no reply.
He told Shrewsbury Crown Court that money, a mobile phone, a watch, a wallet and a bank card were stolen.
The court also heard that the victim's keys were snatched and used to lock him inside, resulting in a charge of false imprisonment.
He added that the card was used to order £32 worth of pizzas, and more than £30 was spent on phone top ups.
Weston, 36, of Purbeckdale, Dawley, Telford, denies one count of robbery, one count of false imprisonment and two counts of fraud.
Prosecuting Mr Shakoor said: “The prosecution case is that Mr Devilliers couldn’t have got it wrong about this defendant being one of two robbers and if you follow the reeds of this it will take you to a defendant who knew of a man with significant vulnerabilities, but has taken advantage of him when Mr Devilliers was doing his utmost to help him out.”
The trial continues.