Mikhaila Peterson shared an update on social media this week—her first since October—to announce her father's return home after spending time in an intensive care unit this fall, where he was treated for pneumonia and sepsis. Those conditions appeared after mold exposure this summer led to a "severe" flare-up of a chronic illness he has been battling since 2017, she said.

Specialists are continuing to work on determining the underlying cause of his illness and are considering a complex array of possibilities from neurological, to autoimmune, to a mixture of both.

Mikhaila said no answers have emerged thus far and he remains "very unwell."

"I'm hopeful he will recover with time," she said in a Dec. 9 video post. "When I posted the last video, I didn't know if he would recover at all. It was really scary and I'm hopeful now, but it's still early on."

Her father's prognosis remains uncertain, but Mikhaila said she is hopeful he is on the road to recovery.

"Things are really bad, but they're not as bad as they were a month ago or two months ago," she said.

Mikhaila first announced her father's health crisis in an August social media post, saying he had been forced to postpone his podcasts and reschedule his European tour due to a "severe" onset of symptoms she said is linked to chronic inflammatory response syndrome (CIRS).

"Jordan Peterson is taking some time off of everything," she wrote in an Aug. 13 X post, saying he has a "genetic predisposition" that results in the immune system's inability to detect and detoxify mould or bacteria in indoor air.

She noted that her father has been battling CIRS since 2017, but the family didn't know what the problem was at the time. CIRS is a long-term condition triggered by exposure to biotoxins in water-damaged buildings that can result in a variety of debilitating symptoms such as fatigue, brain fog, and changes in appetite, according to the National Library of Medicine.

She said his struggles with the condition had intensified over the past year but a recent large mould exposure while helping to clean out her grandfathers' basement had pushed his symptoms over the edge.

He was taken to the hospital by ambulance later that same month and Mikhaila said in an October social media post that her father had spent nearly a month in the ICU before being moved to "a less urgent floor."