Sen. Tim Johnson’s condition has been upgraded from critical to fair four weeks after he was hospitalized for a brain hemorrhage, and he no longer needs a ventilator to help him breathe.

Johnson is breathing independently after using a ventilator for several weeks, most recently only at night, his doctor, Vivek Deshmukh, said Tuesday.

The South Dakota Democrat, who underwent emergency surgery on Dec. 13, remains in intensive care at George Washington University Hospital, said his spokeswoman, Julianne Fisher.

“The senator continues to make progress,” Fisher said. “The next step would be rehabilitation, and we hope that would happen within the week.”

The senator is expected to leave intensive care but remain in the hospital when he begins the rehabilitation process. His office has said that his recovery is expected to take several months.