"We've come a long ways. From three years of sitting, to now able to stand and walk. It's amazing," Cassidy tells us.
Though these aren't the legs Felix was born with, they're the limbs he will rely on for the rest of his life.
"It happened so quick. I lost both of my legs within 27 days of each other," Cassidy explains.
Rob Walker, prosthetist at West Texas Rehabilitation Center, is at Felix's side, working to bring normalcy back to his life.
"We're able to use that model of normal walking as our gold standard for our prosthetic patients to try to get them back to that gold standard," Says Walker.
But with rehabilitation, Walker believes a strong will can be just as important as strong muscles.
"A big story behind all of this is the person who's using that technology, and using that prosthesis, and the will and drive that person has. That's a very important part," Walker says.
"I had one of the girls ask me, 'Why don't you seem to get very excited?' and I said, 'Yes I do! I scream, I shout and I holler!" Cassidy tells us.
And Felix is still hollering, but now, it's rejoicing how far he's come.
"Where I was at, to where I'm at now--it's joyful!" says Cassidy.
For more information on prosthetics or the West Texas Rehab Center, click here.