I received owner information from Chicago Animal Care and Control regarding Duke, as they implanted his microchip, and the owner's information with AVID was not updated. CACC was not able to reach his family.
I left some voicemails, and sent some texts, and I was able to find one of the sons of the registered owner, Christian. Christian needed a few days to get to CACC to pick Duke up, due to his work schedule, but told me "Duke grew up with myself and 3 siblings." He needed to get him back home, and said "they were so worried they would never see him again." Duke is 13 years old.
Christian was able to pick Duke up. He is very grateful that Chicago Animal Control waited for him to come and get him, and that Lost Dogs Illinois paid for his reclaim fee.
Duke is now back with his family he grew up with.
Welcome home Duke boy!