Ford spoke briefly with reporters after attending an advance voting station in Etobicoke, where the mayor said he had made the trip to support Doug Ford, who is running for mayor in his place.
"My brother's going to be the best mayor the city's ever had, absolutely," Ford said.
Ford, 45, withdrew from the mayoral race last month, after a tumour was discovered in his abdomen. He was subsequently diagnosed with liposarcoma, a rare type of cancer, and has undergone two rounds of chemotherapy.
When speaking with reporters, Ford said he was feeling both "a little tired" and "not very good."
Ford said he'll be back in hospital on Oct. 29.
His name remains on the ballot as a candidate for Ward 2 councillor. He represented the ward for a decade before he was elected as mayor in 2010.