Canada functions differently from the US in healthcare law, Canada generally provides very wide protections to physicians. Any obscureness or iffyness is of the opinion of the physician.
This is everything on consent if you want to read the exact definition (Ontario):
“treatment” means anything that is done for a therapeutic, preventive, palliative, diagnostic, cosmetic or other health-related purpose, and includes a course of treatment, plan of treatment or community treatment plan.
http://www.e-laws.gov.on.ca/html/statutes/english/elaws_statutes_96h02_e.htm#BK24
Consent to Treatment
No treatment without consent 10. (1) A health practitioner who proposes a treatment for a person shall not administer the treatment, and shall take reasonable steps to ensure that it is not administered, unless, (a) he or she is of the opinion that the person is capable with respect to the treatment, and the person has given consent; or (b) he or she is of the opinion that the person is incapable with respect to the treatment, and the person’s substitute decision-maker has given consent on the person’s behalf in accordance with this Act. 1996, c. 2, Sched. A, s. 10 (1). Opinion of Board or court governs (2) If the health practitioner is of the opinion that the person is incapable with respect to the treatment, but the person is found to be capable with respect to the treatment by the Board on an application for review of the health practitioner’s finding, or by a court on an appeal of the Board’s decision, the health practitioner shall not administer the treatment, and shall take reasonable steps to ensure that it is not administered, unless the person has given consent. 1996, c. 2, Sched. A, s. 10 (2). Elements of consent 11. (1) The following are the elements required for consent to treatment: 1. The consent must relate to the treatment. 2. The consent must be informed. 3. The consent must be given voluntarily. 4. The consent must not be obtained through misrepresentation or fraud. 1996, c. 2, Sched. A, s. 11 (1). Informed consent (2) A consent to treatment is informed if, before giving it, (a) the person received the information about the matters set out in subsection (3) that a reasonable person in the same circumstances would require in order to make a decision about the treatment; and (b) the person received responses to his or her requests for additional information about those matters. 1996, c. 2, Sched. A, s. 11 (2). Same (3) The matters referred to in subsection (2) are: 1. The nature of the treatment. 2. The expected benefits of the treatment. 3. The material risks of the treatment. 4. The material side effects of the treatment. 5. Alternative courses of action. 6. The likely consequences of not having the treatment. 1996, c. 2, Sched. A, s. 11 (3). Express or implied (4) Consent to treatment may be express or implied. 1996, c. 2, Sched. A, s. 11 (4). Included consent 12. Unless it is not reasonable to do so in the circumstances, a health practitioner is entitled to presume that consent to a treatment includes, (a) consent to variations or adjustments in the treatment, if the nature, expected benefits, material risks and material side effects of the changed treatment are not significantly different from the nature, expected benefits, material risks and material side effects of the original treatment; and (b) consent to the continuation of the same treatment in a different setting, if there is no significant change in the expected benefits, material risks or material side effects of the treatment as a result of the change in the setting in which it is administered. 1996, c. 2, Sched. A, s. 12.
It is of the opinion of a physician if you are capable of making the decision to die, and it can be implied to the physician that you want to die. In general doctors do not need proof, and the legislation is consistent with that common theme as the Supreme Court of Canada and not Canada, has concluded that physicians can make the judgement call:
http://s3.documentcloud.org/documents/1657039/supreme-court-ruling-on-assisted-dying.pdf