Jennifer-Lynn Quinones described her cousin as a hard worker and family man.
Quinones said the 27-year old from Wiliamstown, New Jersey was a father of two small children and was planning a wedding.
She described him as someone who loved cars, and worked as a self-employed mechanic.
The family says right now their focus is on keeping his legacy alive.
"He was just a very compassionate and generous young man and we just want people to know that he wasn't doing anything wrong he was just answering a Craigslist ad," Quinones said.
23-year old Thomas Coffee of Willow Grove, Montgomery County has been charged with Cook's murder.
Police say Coffee lured Cook with the online ad, then shot and robbed him.
A funeral for Cook will take place this Saturday in Gloucester County.