My mother was turned away from a Toronto hospital 3 times and when she
was finally admitted she was abused, neglected and given the least
possible substandard
treatment and care. One month after her release from hospital she died
uncomfortably. I have consulted my lawyer and I have sent letters to
the hospital requesting a meeting with the Chief of Staff. Four
professionals (her palliative care doctor, her family doctor, her
emergency room doctor the night she died at a different hospital and a
full time registered nurse from Riverdale hospital) plus several of
her caregivers within the health care system have confirmed that my
mother was neglected and treated incorrectly. Can I sue a Canadian
hospital?

Just curious: why would you ask this of total strangers on the
Internet if you have already consulted a lawyer?

You need to contact a lawyer that is a member of the Law Society of
Upper Canada.  Try www.lawyerlocate.ca for example.

You seem to be telling just one side of the story.