I think its possible the movie will bring light to the very wrong attitude of how some people think: that children and people with autism (and other disabilies) need to be eliminated, that they dont belong, that they are societys burden.... and give the message how wrong that way of thinking is. Its hard to tell but from what i have read it seems the boy goes from thinking the child better off dead to knowing he was wrong to think that way....with insights to the consequences of what he did and how it effects others and the family. AND the ultimate message might be that everyone, disabled included can provide benefit to this world. That even tho somone might be considered a burden others see that person as a joy.
I guess i would have to see the movie to know for sure if it brings this message or not...