"Today was hard. I think he's exhausted," his mother, Maureen McGowan, said Friday evening. "Two ambulance rides and a plane ride are probably a lot for him."
The 18-year-old's struggles since breaking his neck on Aug. 10 have been chronicled almost daily in videos posted on You Tube and Facebook.
They include an especially poignant moment when his brother, Charlie McGowan, 8, sees him for the first time in the hospital.
"You're taking over. Now you're faster at running. You're quicker," Danny tells the boy. "You're the man of the house now."
At times, in his daily updates, Cox displays a remarkable attitude and even a little humor as he lies in bed, unable to feel his legs or most of his body.
"I'm doing a lot better today," he says on Day Three of his hospitalization, lying immobilized. "I can, you know, talk a lot easier and swallow.
"I can't really move my legs or arms at all still. And I have terrible itching all over. Those are pretty much the only bad things. Other than that, it's OK."
During his high school years, Cox shared much of his life on social networking sites, so doing so now is almost natural for him, said his mother.
A website, www.DannyCox888.com, displays the videos and provides a way for people to donate for the costs of his rehabilitation not covered by his Kaiser medical insurance.
One photo shows a smiling Cox prior to his accident, when he was a member of the Petaluma High School track team. He is holding two of the girls on the team, one on each arm.