MAIN IDEA HIT ME

I think the main idea is that disabilities don't only hit the truly disabled person but to those surrounding them also. Catherine is a changed person through David, he perspective of life was punched in the face from Davids disability ( sorry bad example ) don't you think she would be less thoughtful like Kristi if it weren't for David. And also even if David isn't in the foreground all the time he is sitting in the background of every scene.