Watch: Toddler With No Arms Pushes Pacifier Into Baby Brother's Mouth

When Katie Whiddon was told that her first child, a boy named Camden, would be born with no legs or lower arms, she worried about the quality of life he would have.

"My sweet baby boy is never going to be able to walk, he is never going to be able to ride a bike, he is never going to be able to brush his own teeth, he is never going to be able to bathe himself, he is never going to be able to go to the bathroom by himself, he is never going to be able to play like a normal child, he is never going to be able to hold someones hand, he is never going to be able to wear shoes, he is never, he is never, he is never," Whiddon wrote on her blog, Admirably Diverse. "Those are the thoughts that went through my head. Is that a true quality of life? Would I want to live like that? Do I want my child to live like that?"

Camden is three-years-old now, and while Whiddon was right about some of the things he won't be able to do, she realizes now that there's so much more Camden can do — like help to calm down his baby brother.

As Today reported, Camden helped his crying baby brother by pushing his pacifier back into his mouth in a now viral video posted to Whiddon's Instagram.

Camden was diagnosed with Amelia-phocomelia syndrome, a rare congenital anomaly that causes parts of the skeleton not to grow, soon after he was born. Despite his limb difference, though, Camden can also do some of the things Whiddon worried he'd never accomplish, like brush his own teeth and wash his face.

"He is your typical three year old boy," Whiddon wrote on her blog. "He picks his nose, thinks farts are funny, never stops talking, and is always messing with his younger sister. He can draw, paint, sit up by himself, feed himself, wash his own face, brush his own teeth, climb up stairs, and so many other things."

Refinery29 has reached out to Whiddon and will update this story when we receive a response.