She told me that the centre provides horses and arenas for different therapists during the week and that I had to get permission from the therapist and patient/ guardian/ parent before sitting in to observe the session. Tomorrow she is sending me a detailed list of the names of the therapists, times of their sessions and what 'practice' they belong to. I plan on picking some times that are good for me and contacting the therapist to see if I'm able to attend their session. I hope to get three times during a week to watch and learn as much as I can in the given time. Hopefully the therapists speak English or French, that would make my life much easier.
What is hippotherapy?
"Hippotherapy is a physical, occupational or speech-language therapy treatment strategy that utilizes equine movement as part of an integrated intervention program to achieve functional outcomes. It has been practiced in North America for more than 30 years and is practiced in many countries throughout the world." 
What hippotherapy does.
"Physically, hippotherapy can improve balance, posture, mobility and function. Hippotherapy may also affect psychological, cognitive, behavioral and communication functions for clients of all ages. Clients who may benefit from hippotherapy can have a variety of diagnoses: examples include Cerebral Palsy, Multiple Sclerosis, Developmental Delay, Traumatic Brain Injury, Stroke, Autism and Learning or Language Disabilities. However, hippotherapy is not for every client. Each potential client must be evaluated on an individual basis by specially trained health professionals." 
"When certified by the American Hippotherapy Certification Board the therapist is a hippotherapy clinical specialist. " 
Requirements to get a Certififation.
(In the United States)
1. Currently licensed or certified to practice as a physical therapist, occupational therapist, or speech and language pathologist in the United States or the equivalent in other countries.
2. At least three years of full time or the equivalent (6,000 hours) experience in the practice of physical therapy, occupational therapy, or speech and language pathology.
3. A minimum of 100 hours of one-on-one direct treatment in clinical practice using hippotherapy within the three years prior to certification application deadline. Please note that
treatment experience that is part of an educational course or mentoring process does not qualify for this eligibility requirement.
4. Experienced and comfortable working with horses. Independent skilled riding ability.
5. Completion and filing of Application for the Hippotherapy Clinical Specialist Certification Examination.
6. Payment of required fees.