Actually, they've been training miniature horses as service animals for quite a while now. They can do a lot for folks with disabilities.
http://www.guidehorse.org/
(Be sure to read the part about their shoes!)
The biggest advantage to them over a dog is that they live a lot longer. Training a
licensed service animal is a big investment of time and money. So service training agency can offer a lot more with a trained horse.
But this seems - well - a little over the top...
