Last Saturday he wandered away from his father and grandfather while they hunted for a Christmas tree.
"Back of my mind, sure-the kid's back with his dad, but that was my big mistake," says Derek's grandfather. "Because the dad was too far ahead of him and the boy never did catch up with him."
The concern is winter weather will catch up with Derek. Authorities are telling his family the chances of Derek surviving in the bitter cold and waist-deep snow are slim.
"Right now you're down to the point where you've got to be facing reality, but, you know, I still have hope," says the father of the boy.
That hope springs in part from the fact that Derek, nicknamed Bear Boy by his father, is an avid hunter familiar with the woods. And searchers have found signs he may be using those skills to survive.
So far, however, there has been no sign of Derek.
One of the searchers says "There's some sadness, everyone feels the loss. Everyone who has kids thinks, man if it was my little guy out there."
"And we re going to keep looking until they tell us to stop," says another.
It may be up to volunteers to find Derek. Official search and rescue efforts ended Sunday night. Derek's father, who caught pneumonia while searching for his son, says the family won't just give up.