David Michael Prosser commented on your link.David wrote "Something that's good for the horse and for the human has to be good. This kind of therapy beats all medications."
I'm fortunate in that my wife cares so much for both people and animals. There are times that I feel without her support I would have fallen and I know she takes that level of support and commitment with her to the stables. No horse should feel alone, be neglected or suffer ill treatment if she is on the job. If I were able to financially suppport her venture into having a stable which dedicated itself to the rehabilitation of neglected animals and to the therapy for those who woulf benefit for contact with animals I would not hesitate because I know she cares so much.
If you have some land or have a horse that perhaps you can't be with all the time why not offer your local mental health team a chance to offer some therapy sessions to those in need. Your horse gets more company and those in need get the chance to start healing.