Leroy suffered a knock to the head and had to be kept in hospital for five days due to a blood condition he has called haemophilia A.
The PlayStation, which had been in the car, was wrapped in a blanket and left at the relatives' Rimu St house.
"When we got into the children's ward all he was talking about was his PlayStation for Christmas."
Miss Coyle went back to the house to get the PlayStation for him to use in hospital, but it had disappeared.
She said other people had been in and out of the house and believed the person who took it knew Leroy was in hospital.
"I didn't know what to say. I couldn't replace it ... I can't afford to replace it."
Miss Coyle said she could not afford to buy her son such things, but had jumped at the opportunity to get the games console in a hire purchase plan.
The PlayStation cost about $300, which she would still have to pay off, despite it being stolen.
"I've got photos of him unwrapping it on Christmas Day with a big smile - but he didn't even get to play with it.
"It's just heart-breaking that someone would do that, knowing that this little boy's in hospital after a car accident.
"That was his biggest thing on Christmas Day - PlayStation." The information has been passed on to the police, and Leroy and his family have now returned home to Tikokino.