The schoolboy, called Ethan, was made to hold a 44-pound log for two hours every day for a week, US cops have claimed.
He was being punished for "not knowing 13 Bible verses", it was reported.
Wisconsin couple Timothy and Tina Hauschultz, along with their 15-year-old son, Damian, have now been charged over the little boy's death, Newsweek reported.
Authorities claimed the couple's teen son had kicked and punched the little boy at least 100 times, standing on him while he was face down in a puddle.
Reports suggest the little boy was then buried alive in "his own little coffin of snow", Fox reported.
Manitowoc County Sheriff's Office said: "Ethan had been performing punishment ordered by Timothy which required Ethan to carry a heavy wooden log, weighing approximately two-thirds his body weight, while being monitored by Timothy’s 15-year-old son."
They added: "Over the course of 1-1.5 hours, the 15-year-old hit, kicked, struck and poked Ethan numerous times. He repeatedly shoved Ethan to the ground and rolled the heavy log across Ethan’s chest. He stood on his body and head while Ethan was face-down in a puddle.
"He ultimately buried Ethan completely in snow. Timothy and Tina eventually transported Ethan to the hospital where he was pronounced dead."
The schoolboy died in April 2018 from hypothermia and blunt force trauma to the head, chest and abdomen.
Ethan's mother Andrea Everett spoke out after his death, saying: "When I got there Ethan did not have a heartbeat and his temperature was 23 degrees.
"They worked on him for five hours, giving him CPR the entire time, and still couldn't get a heartbeat. There was no brain activity."
She added: "I want justice for my son, and the person responsible should go to jail for a very long time."
Timothy Hauschultzm 48, has been charged with felony murder and felony contributing to the delinquency of a child along with four other charges.
Tina Hauschultz, 35, was charged with failing to prevent bodily harm and intentionally contributing to the delinquency of a child.
The couple were reportedly the court-appointed guardians for victim Ethan.
Damian Hauschultz was charged with first-degree reckless homicide and six other charges.
The accused were arrested on Friday.
All three are expected to appear in Manitowoc County Court this morning.
