LOUISVILLE, Ky. (WHAS 11) -- A young man once paralyzed from the neck down was able to walk by himself 8 months after a mysterious illness.

He was able to take the steps without any help. With a little help and a deep breath, Shane Roof was able to walk.

Then his dad lets go and he was able to walk on his own. There was no help needed, but his dad was there just in case.

“He keeps on pushing through. We are proud of him,” said Roof's dad, Darrell Roof.

It's not easy for Shane, but he's determined to take every step he can.

“I never thought about not being able to do it,” Shane said.

Shane, 15, has come a long way since the summer. He was in a hospital bed with limited mobility from the neck down. Initially, he was paralyzed from the neck down after suddenly getting sick after cutting the grass.

Doctors still don't know what caused the paralysis.

“I have definitely improved so much," Shane said. "I am so grateful that everything is starting to come back. It's amazing my arms are starting to come back and so are my legs. It's pretty cool."

And this was pretty cool, too.

In rehab, Shane was able to walk flights of stairs.

“To see him go up the steps—two flights—that was a big feat, and I was showing all my buddies at work,” Darrell said.

With more movement, Shane is now able to use his Christmas present—a smartwatch from his dad— and pet his new pup.

But with his mobility came something else that still makes his mom emotional

“What it's been for me, when he was able to stand up and put this arm around me, that hug it brings tears to your eyes,” Alexandra Roof said.

Shane is working hard, walking and doing his school work from home. He's not giving up - just like his shirt says.

Words he didn't live by until now—words he hopes will inspire others.

People often ask his family, “Does that boy ever have a bad day?"

"I was like 'nope,'" Darrell said. "He's got a goal set and he's moving forward."