Now, his family is sharing their emotional plea for help.
"He's been gone too long, he needs his medication, he's probably confused, cold… he needs to be home." said Esnelia Vargas, Jose Arevalo's daughter.
The daughters of 83-year-old Arevalo say he walked out of the family's Berwyn two-flat a little after 1:30 p.m. last Thursday and hasn't been seen since.
A Ring camera caught a brief image of him crossing the street a block away, but from there, the trail goes cold.
His family says Arevalo has dementia, which has become severe over the past year, and likely worse now that he isn't taking his medicine.
They've distributed more than 2,000 fliers with his picture and information.
Family, and even complete strangers, have been searching large portions of the city where he has lived in the past, like Little Village, Brighton Park and along Cermak Road.
"We've had people reach out and say, ‘well we might have seen him, we’ve gone out and looked.' Unfortunately they've all been — hasn't been him — but everybody's vigilant, everybody's out there looking," said Alejandra Arevalo, Jose's other daughter.
"We're asking the community to be vigilant out there, um, obviously he could have changed clothes, someone could have given him something, um changed his hat, from the Cubs hat he was last seen wearing," said Commander Michael Fellows of the Berwyn Police Department.
Berwyn police have also used teams of bloodhounds to track Arevalo's scent, but they were only able to do that for several blocks.
If you do see someone who looks like him, you're encouraged to take a cellphone picture and call the Berwyn police non-emergency line.