Huh? Ages?
Spoilers,
So they stole a baby 12/years ago for his heart for their son who looks about 7? By the end of the movie the boy looks 14. The boy in the bed while obviously sick and atrophied still couldn't be older than the other boy. That completely negates the plot making any sense. You can't kidnap one child to save the life of one you haven't even had yet.