Ian Wilkinson, 68, was left in a coma after eating a Beef Wellington cooked by Erin Patterson during a family meal.
Three people, including Mr Wilkinson’s wife, Heather, died after eating the meal, which police believe may have contained death cap mushrooms.
Ms Patterson is not facing charges over the case and has said the mushrooms used in the beef Wellington were bought from a store three months before serving them to the group.
In a statement, Mr Wilkinson’s family said: “This milestone marks a moment of immense relief and gratitude for Ian and the entire Wilkinson family.
“The Wilkinson family would like to extend their heartfelt thanks to the Leongatha, Dandenong and Austin Hospitals for their unwavering dedication and exceptional care that played a pivotal role in Ian’s recovery.
“The medical team’s expertise and compassion have been a source of comfort and hope throughout this journey."
The mystery unfolded after Ms Patterson served lunch at her home in Leongatha, Victoria on July 29.
Shortly afterwards, her former in-laws Gail and Don Patterson, alongside Gail’s sister Heather and her husband Ian fell ill.
Ms Patterson’s estranged husband could not attend at the last minute.
Within days, Heather, 66, Gail, 70, and Don, 70, died.
Suspicion initially fell on Ms Patterson, as she was not taken severely ill and had cooked the meal.
However, she has strongly denied any wrongdoing.
In an interview with the Australian newspaper last month, she said: “I lost my parents-in-law, my children lost their grandparents.
“And I’ve been painted as an evil witch.”
The 48-year-old added in a statement to ABC: “I am now devastated to think that these mushrooms may have contributed to the illness suffered by my loved ones.
“I really want to repeat that I had absolutely no reason to hurt these people, whom I loved.”