Joe Geeling battled cystic fibrosis throughout his short life and became known as a little angel who touched the lives of all he met.
Michael Hamer, 14, was a loner and an isolated youngster who had been bullied at school.
Tragedy struck when Hamer, now 15, developed an obsession with 11-year-old Joe.
Hamer was jailed for life yesterday after pleading guilty to murder and was told he must serve at least 12 years.
Hamer smashed Joe around the head 10 times with a frying pan then stabbed him 16 times in a "frenzied" attack after the youngster had spurned a sexual advance.
He had lured Joe back to his home from their school in Bury, Greater Manchester.
After killing him, he hauled the youngster's body into a bin, wheeled it to a nearby park and dumped it in a tree-lined gully where it was found the next day, March 2, 2006.
Hamer pleaded guilty before his trial was due to start yesterday at Manchester Crown Court.
He was jailed for life, the judge recommending he serve at least 12 years.
Hamer will spend his time in secure accommodation receiving psychiatric treatment.
The court was told yesterday Hamer had recently admitted making a sexual approach.
Mr Justice McCombe said: "The rejection of the advance was the immediate triggering event of what you did."
The attack started with 10 blows to the head with a frying pan and continued with a barrage of stabbing blows with three kitchen knives.
Hamer dragged Joe's body downstairs and through the kitchen before taking it in a wheelie bin to Whitehead Park where it was found the next morning. In his pocket was a letter Hamer used to coax him to his house.
The loss of their "very brave and kind-hearted little lad" has devastated the Geeling family, Manchester Crown Court was told.
In a victim impact statement, Joe's parents, Tom and Gwen Geeling, said: "Our son meant everything to us. We spent many happy years grooming him into the smart, witty, loving young man that he had already started to become.
"In spite of the drawback of being born into this world with cystic fibrosis, and enduring more than his fair share of hospital visits ... he understood those were the cards God had dealt to him and together we made the best of what we had."
Mr Geeling said: "My wife and I privately weep all the time. We weep about what we could, would and should be doing with Joe now."
He said Joe's younger brother James, who has just turned seven, is sometimes inconsolable.
"Putting him to sleep some nights can take an eternity."