I have a horse-enthusiast friend that owns two Morgans. She loves them dearly, but she was involved in a car accident a few years ago and is now suffering severe back issues. She is finally coming to realize that she will likely never be able to ride again and ought to sell her horses on to a home that will be able to ride them.
What I wanted to know was whether it would be at all plausible for her to consider trying to train one of her horses to drive. Would driving be easier on her back? I don't really know much about driving

. Is it very difficult to train a horse to drive?
I know this is probably a long shot. But I feel so horrid that she is having to give up her equestrian hopes and dreams.