Darragh had been told that the goalie would be able to do a video chat with him, but Anderson and his wife, Nicholle, herself a cancer survivor, made the journey to see him instead.
"It was a huge surprise," Liam's mom Lisa told the Senators website. "Liam had no idea about any of this, and when Craig walked off the elevator I was shocked."
Darragh has Prader-Willi syndrome, a disorder that affects about 1 in 10,000 to 30,000 people worldwide.
The visit from the Andersons no doubt brightened his day and Craig left an open invitation for Liam to attend a Senators game, complete with locker room visit as soon as he is feeling better.
"He loves the [Senators]; he's like their couch-coach," Lisa said. "I think he's really, really, really excited. I think he was a little shellshocked … it's got to be the best day of his life."