Hayden Ng loses his temper often and vents his anger by punching his older brother and slapping or scratching his mother, reports The Straits Times.
Once cheerful and obedient, the six-year old's temperament has changed since he was diagnosed in October last year with Stage 4 neuroblastoma, an aggressive nerve cancer.
"I've not seen him laugh since then," says his mum, housewife Low Xueli, 31, in Mandarin. Doctors operated on him in February to remove a 9cm by 7cm tumour in his abdomen.
By then, the cancer had spread to his bones and bone marrow. He went through intense doses of chemotherapy, starting in October last year.
But his body did not respond to the treatment even after 12 cycles. "As the cycles went on and he did not get better, he grew depressed," says his father Eddie Ng, 42, a manager.
Hayden would kick the nurses and refuse to take his medication. "He kept asking, 'Why am I still not well?'," says Mr Ng.
"It was heartbreaking for us." Hayden stopped attending kindergarten classes this year to undergo treatment. His parents hope he can go to K2 next year. His illness has affected his older brother, 10-year-old Hendry. Another brother, Herman, is four.
Pointing to some pictures in their three-room HDB flat in Toa Payoh, which show a chubby and smiling five-year-old Hayden, Hendry says: "I want him to be what he used to be. He was cute and happy. He never used to shout, throw things or hit people."
While Hayden takes his anger out on him regularly, Hendry does not retaliate. "I love him and I know he's in pain." Hayden, who does not say a word during the interview, is now bald and his skin is darkened from chemotherapy.
In August, doctors told the family that his body could no longer withstand chemotherapy and recommended a bone marrow transplant.
When Hayden's case was referred to the Make-A-Wish Foundation Singapore by the Children's Cancer Foundation, he said his greatest wish was to have a laptop. He also revealed that he was a big fan of home-grown film Ah Boys To Men.
The laptop, Hayden says, was to keep him company after his transplant, as he had to be isolated after the surgery. His wish came true last month.
His family was taken to Chin Lee Restaurant in Bedok North, which serves Teochew food and is helmed by award-winning chef Eric Chua.
Mr Chua sponsored a meal for the family and Hayden was treated to his favourite dim sum and duck dishes. Some cast members from Ah Boys To Men - Noah Yap, Wang Weiliang, Maxi Lim and Charlie Goh - then came to dinner and presented him with the laptop.
They also gave him earphones, gaming gadgets and his favourite game, Minecraft. Madam Low says: "For the first time in a long time, he was happy. He kept asking, 'Mummy, is this real? Are they really here?'"
A day after that dinner, he went for the bone marrow transplant. His parents say he did not struggle or hit anyone that day.
"When his wish came true, I think he saw some hope. He also told me, 'Mummy, I'm sorry for hitting you. I can't control myself'," Madam Low recounts.
As Hayden's body could not be cleared of cancer cells at the point of the transplant, there is less than a 20 per cent chance that he will recover fully.
"We really need a miracle," says Madam Low, who takes him to hospital once every three days for a blood transfusion.
Still, she says the family is deeply grateful to everyone who has helped them.
Mr Ng adds: "We also have a wish. We wish for our whole family to be at peace and for the chance to celebrate Hayden's birthday in February."