The 14-year-old boy suffered brain injuries when his skull was shattered, his father said.
Sean Connolly and family members have been going door to door in Park Ridge in the neighborhood where they believe the attack happened.
Since his son was knocked unconscious, they said they don't know exactly where it happened.
Connolly says police believe they know who attacked the boy, but he is hoping neighbors may have video from security cameras or ring doorbell cameras that may have captured the beating. Connolly especially hopes to learn what blunt object was used to cause his son's severe injuries.
The father says he wants to spread the word quickly before any video would be erased. He's asking anyone who may have any information to call the Park Ridge police.