Coun. Rob Ford is back in hospital and undergoing chemotherapy for two tumours that were discovered in the fall, his brother Doug Ford says.

"It's a fight," Ford told CBC News, adding he had just left the hospital where Rob Ford is being treated.

"It's like politics. You're up one day, you're down the next. It's a real challenge," Doug Ford said.

He said his brother, who now represents Ward 2,  is in "relatively good spirits" and appreciates the prayers and messages of support he's receiving.

Doug Ford said the former mayor is undergoing eight cycles of chemotherapy.

Rob Ford, 46, revealed in October he had a growth on his bladder after being hospitalized for several days due to abdominal pain.

In November, Doug Ford said his brother actually had two tumours on his bladder.

Last May, Ford underwent cancer surgery to remove an abdominal tumour after he was diagnosed with liposarcoma — a cancer that grows in fat cells. 

He was diagnosed with that tumour in September of 2014, forcing him to withdraw from the Toronto mayoral election campaign.