When you say "healing dog", I think you mean therapy dog?
If so, here is a link that may point you in the right direction:
http://www.tdi-dog.org/whatdo.html , this is the web site for Therapy Dog International, INC.
Therapy dogs are not to be confused with "service dogs"; for example a dog used by a blind person for navigation, or a dog that helps someone who is paralyzed and immobile. A therapy dog and their handler provide comfort and companionship to people in nursing homes, hospitals, rehabilitation centers, and institutions. They enrich the lives of not only patients, but, their caregivers, too.
I hope to use my 3 year old Golden Retriever in therapy work in a year or two. Goldens tend to have long puppyhoods, and right now her interests lie more in how many frisbees she can catch in a day, than being calm enough for therapy work! Good luck with your efforts, and let me know if you need anymore info. I'd be happy to help.