Grey acted opposite Swayze in "Dirty Dancing," while Thompson appeared with him in "Red Dawn."
"I wish him all my love, and I have great faith that he is a fighter, and he will fight this," Grey told Usmagazine.com. "The thing about the human condition is that everyone has to deal with something like this, and he is the kind of guy who fights it."
Thompson said: "I've known Patrick for so long. He's a really great guy. ... He will be resilient."
Notable deaths of 2014 [PHOTOS]
Hilary Duff 'open to' Lizzie McGuire reunion