Tripp Halstead, the boy critically injured by a falling tree limb almost four years ago, turned 6 on Sunday.
Tripp's mother, Stacy, marked the occasion with a lengthy post on Facebook.
"Almost four years ago, I thought our life was over. Not only Tripp's life but mine and [husband Bills also," Stacey Halstead wrote. "I know it's not the anniversary of Tripp's accident but each year that he is here with me makes me relive that tragic day."
Back in 2012, Tripp Halstead suffered a traumatic brain injury when a tree limb fell on him at his daycare. Millions of people have followed his recovery on a Facebook page set up by his mother, Stacy.
Stacy wrote that after the accident, she needed to know if her child was happy.
"And now, I don't think a day goes by that he doesn't give us a truly genuine happy smile. It is not forced or a reaction from the brain injury. It is truly because he is happy," she wrote.
Tripp suffered a traumatic brain injury in the accident. Over the years, he has continued to make progress. On Monday, Stacy wrote that doctors noted "how happy and healthy he is looking these days." Last month, he ventured into the ocean while on vacation with his family.
PHOTOS: Tripp Halstead