It is most likely because sleep helps strengthen the memories you have made during the day.
I'm not entirely sure why holistic treatments would be controversial in animals. Perhaps what makes them controversial is the fact that we tend to assume we know what makes them holistic and how they will be holistic for the animal - this isn't necessarily the case, as we can only make a good guess about it.
I believe it is : They are more likely than people without disabilities to report poorer overall health.
