Neither adult sought medical attention for the injury.
Gray would regularly verbally abuse and swear at the child, and discipline him "harshly", the summary said.
"The victim ... became very intimidated of the defendant Gray and would cower when he entered the room."
In June 2018, Gray was caring for the boy and another child in Waikanae when he became angry with the victim.
He grabbed the child by the left leg and used his hand to twist the leg violently, causing a spiral fracture in the victim's lower femur.
Gray did not call an ambulance, and instead called the other adult, asking her to come to the house.
When she arrived at the house she called an ambulance, and the child was taken to hospital.
The boy had to undergo two surgeries to insert and modify metal pins in his leg. He had to use a wheelchair for several weeks as he recovered.
A victim impact statement from the boy's grandparents said he walked with a limp for a long time after the injury, was "traumatised" by the subsequent operation to remove the pins from his leg, and was often kept awake by the pain from his wound.
Neither Gray nor the other adult fed the victim regularly after the broken leg incident, the summary said.
He was not taken back to daycare until late August. Staff members there noticed a large yellow bruise on the side of his face, and noted he had lost a "significant" amount of weight.
The other adult told staff the boy had fallen out of his wheelchair onto a deck and hit his face. No medical attention had been sought for the fall.
Following that visit to daycare, the victim was kept at home by the defendants.
The summary also said between July and September that year, Gray kicked the child in the head at least once.
"The defendant Gray was wearing shoes at the time and the kicks caused pain to the victim. It is unknown what level of bruising or injury was sustained from the kicking."
The other adult was present at the time and "took no reasonable steps" to stop the assault.
Gray was also known to smack the children on their hands to discipline them.
The child was eventually picked up by Oranga Tamariki and police on September 6, 2018.
"He had two black eyes, extensive bruising over his back, left, and right thighs and hips and bottom, and some bruising on his arms and stomach," the summary said.
The child also appeared underweight.
He and his siblings were taken into care and received medical assessments.
Both defendants declined to comment to police.
In court today, Gray quietly shook his head as Judge Stephen Harrop read out the details of his offending.
He had earlier pleaded guilty to the charges.
Judge Harrop said he would have given Gray a prison sentence if it wasn't for mitigating factors such as his own difficult upbringing.
"A prison sentence could well be justified," he said.
He felt Gray had already been strongly deterred by time spent on remand in prison. He did not see it as being in the public interest to sentence Gray to prison now when home detention could be substituted.
He sentenced him to nine months of home detention.
Gray's co-defendant's charges are still before the court.
