Ray O’Sullivan, 33, who suffered a severe head injury in a car accident in 1999, requires the bike to get around.
He has been left housebound following the theft.
His mother, Mary, from Muckross, Killarney, yesterday said the €13,000 bike, which has a special slow speed of 30km/h, had meant everything to Ray.
“I’m so mad that people could stoop so low as to steal it. He has worked so hard to get this far,” she said.
“It had opened up a new life for him to be independent and get around town.”
Ms O’Sullivan said Ray had taken the bike inside all weekend as he feared it could be taken, due to the large crowds in Killarney for the bank holiday weekend.
“He was conscious there were huge crowds of people around all weekend, so he felt it better to keep it inside his apartment at Riverside.’’ But she said he and his sister decided to put it back outside, on Sunday night, so they could clean the floor of the apartment, which had wheel marks.
“That was at midnight but by the time he woke up at 7am on Monday it was gone,” she said.
The family, which pleaded for the return of the bike, registration number 08 KY 2802, believes it was targeted by a group of thieves.
“He is so dependent on this bike to get around, we are all devastated,” his mother said.
Gardaí, meanwhile, are continuing their investigations.