I agree with you, and think that it would be downright dehumanizing to think that your wife's cousin doesn't have a purposeful/meaningful life.
My worry is that someone in Scooter's position has already been shuffled away. We don't know how Scooter perceives his situation, but we should be worried that he feels trapped, futile or meaningless.
Based on my experience with kids, scooter most likely feels trapped for various reasons:
1 - lack of internal coping mechanism (never taught that its ok to feel a certain way)
2 - the realization that he IS different without the accompanying external validation that it's ok to be different.
3 - a mostly aimless daily routine were one just waits out their days
4 - poor or no support network
This is not much different than kids put into the Children's Aid system. Now that's another shit show that needs fixing.
My worry is that someone in Scooter's position has already been shuffled away. We don't know how Scooter perceives his situation, but we should be worried that he feels trapped, futile or meaningless.