The Magic Meadow — Alexander Key

In the dark of a grim hospital ward, five children escape to another world

They call themselves the incurables. They are five children doomed to spend their lives in Belleview's Ward Nine, unable to walk, care for themselves, or even take a trip outside. Their days are gloomy, but they have one another, and at night they play the game. Whispering about places that could never be, they build worlds so vivid that they almost seem real. And then one night, their dreams come true.
 
While the others sleep, Brick closes his eyes and thinks harder than he ever has about the place he calls the Magic Meadow -- a lush hill where dandelions grow. When he opens his eyes, he has been transported. The meadow is real, and with his friends at his side, he will return there again and again -- to learn, to walk, to live.