An Oshawa father is the latest member of his family to die after suffering stabbing injuries during a horrific outburst of violence last weekend at a child's birthday party.

Police said Friday that Rick Kelly, 29, died overnight of what is being termed "unforeseen complications."

Two days earlier, his son Nathan, 3, died in Toronto's Hospital for Sick Children.

Before he died, Kelly made a posting on the Facebook social networking site declaring he'd lost "two angels" and that he would start rebuilding his life. He thanked people for their expressions of support.

A friend of the family told The Canadian Press that she'd been chatting when Kelly about 90 minutes before he started going downhill.

"It's distressing for me. He was laughing and talking to me and everything, and he was fine," the friend, who did not want to be identified, said Friday.

"He told me he was coming home this weekend. This is what makes it so much worse."

On Saturday, Leslie Kelly, Rick's 26-year-old wife, died of stab wounds incurred while trying to protect her family. However, she lived long enough to call 911.

Another son, five-year-old Riley, was also wounded in the attack. He is expected to survive. "He understands some of it, but not much of it," the friend said.

The family had been celebrating the birthday of Brandon Kelly, 11, who wasn't injured in the attack.

Police shot and killed the attacker, Gino Petralia, 47, in an adjacent townhouse unit.

Petralia showed up at the party. His son Steven McLean, 13, Rick's half-brother, had been taken in by the Kellys after the boy's mother died this past summer.

Rick asked Petralia to leave, which may have triggered the attack.

Petralia had been suffering from mental health problems for about a decade and was on social assistance.

"Brandon and Steven are just devastated and they're both afraid to go back to the house," the friend said.

"I don't say I blame them because the crime scene is just so horrific."

The family had planned to donate Nathan's organs to help other children. Private funeral arrangements had been planned for Nathan and Leslie.

Two trust funds have been set up in support of the Kelly family, along with plans for  benefits.

"Their Christmas so far is going to be amazing even though their mom and their dad and brother aren't there any more," the friend said of the surviving boys.

Donations to the "Kelly Family Trust" can be made at any CIBC Branch via Account # 00892/03-22938 or through any TD Canada Trust branch via Transit #3184 Account: # 6322034.

Rick's death makes him Durham's sixth homicide victim of 2008.

With files from The Canadian Press