Officials say Matthew Abraham, who also goes by the nickname "Austin," sustained the injury while mountain biking last week at Henry Cowell State Park in Felton. Authorities believe he is "at-risk" because he has been disoriented ever since he was hurt. Police think he could be anywhere and want to bring him home as soon as possible.
Abraham was last seen by his parents at his home in Scotts Valley Wednesday night around 9 p.m. They had been keeping a close eye on Abraham after he was hospitalized following his 50-foot fall off a trestle in the park. He suffered a severe concussion.
Searchers are looking in areas between Scotts Valley and Henry Cowell State Park. A command post has been set up and at least three K-9 units have been brought in for the search.
"I went and visited him yesterday and while he was home and he was saying how he slips in and out of knowing what he was doing," said Brooke Prouty, Abraham's friend.
Then, for some unknown reason, Abraham left home without his phone or wallet. He also didn't make it to class on Thursday at Cabrillo College.
"Mostly just because of the head injury they are concerned something might be wrong with him or he might be in danger," said Santa Cruz County Sheriff's Sgt. Joe Clarke.
Teams are scouring Henry Cowell Park, area schools, anywhere that may be significant to Abraham. His friends and family meantime are passing out flyers and doing what they can to help.
"He just has an amazing heart and he would be doing this for us," said Ben Durham, Abraham's friend. "It's been such a roller coaster. I mean we all heard about his fall on Saturday and his mom said she felt like they turned the corner and everything was going to be OK and then this happens," said Mary Dettle, Abraham's former teacher.
It seemed as though Abraham thought the same. He posted a YouTube video just on Wednesday saying, "I'm going to be just fine. Better than ever even. I promise I'll see you again."
More search teams will arrive Friday morning from Santa Clara and Monterey counties.
Anyone who sees Abraham should call 911.