You will want to find out if the person left a will. Some people file their will with the estates division of their local court, but it could just as easily be with their lawyer, in a safety deposit box, or hidden in a drawer at their home. Once the will is located it may or may not go to probate in the courts to decide on its legality. The executor of the estate carries out the wishes contained in the will.
If the person dies without a will (intestate), the estate will be distributed according to the law. You may want to contact a lawyer. If someone passes away and there are no relatives in Ontario, you may wish to call the Estates Section of the Office of the Public Guardian and Trustee to discuss what to do next.