SINGAPORE - A storekeeper who needed a place to stay and was given space at his brother's flat in Sembawang repaid the kindness by assaulting his brother's stepson.

The attack was so vicious, the 13-year-old suffered a fracture at his left eye socket and sustained a partial muscle prolapse near the area.

The 46-year-old man, who cannot be named due to a gag order to protect the teenager's identity, was jailed for one year and three months on Thursday (Nov 29) after he pleaded guilty to causing grievous hurt to the secondary school student.

The court heard that the man lived in the flat with his brother, the child and his 10 siblings, and the children's mother.

Deputy Public Prosecutor Angela Ang told District Judge Eddy Tham that the storekeeper was entrusted to look after the 11 children on his days off.

On March 20 this year, he told the boy to heat up some food for him but the teenager instead got his younger sister to do it. The storekeeper was the only adult in the flat at the time.

When he learnt that the girl was preparing the food, the storekeeper became angry and kicked the boy twice. The teen was then sitting on the living room floor.

DPP Ang said: "The victim cried immediately. After the assault, the accused returned to his room while the victim remained lying on the floor of the living room in the unit."

After the victim told his mother and stepfather about the incident, they confronted the man, but did not make a police report.

The boy started vomiting at around midnight and the next morning. It was then that his stepgrandmother spotted his injury.

He told her what happened and she alerted the police about her son, the storekeeper.

She also called for an ambulance as the boy was still vomiting. The teen was taken to KK Women's and Children's Hospital.

The court was told the hospital's ophthalmology team plans to review his case and if he remains stable, he will not need further treatment.

The accused, who was unrepresented, told the court that the boy had stolen cash from him.

Before handing down the sentence on Thursday, Judge Tham said: "To vent out your frustrations on a young child is unacceptable. You could have blinded him."

For causing grievous hurt to his victim, the man could have been jailed for up to 10 years and fined or caned.