Direct answer
In Ontario, a substitute decision-maker (SDM) makes health care or personal care decisions for a person found incapable of making those decisions. Under the Health Care Consent Act, 1996, SDMs follow a statutory hierarchy: guardian of the person, attorney for personal care, then next of kin (spouse, parent, child, sibling). The SDM must follow the person's prior capable wishes if known, or act in their best interests. An autistic adult can proactively appoint their preferred SDM through a power of attorney for personal care.
Start with the short answer, then reveal deeper context where helpful.
Substitute decision-making in Ontario is triggered when a health practitioner determines that a person is incapable of making a specific treatment decision. This is decision-specific — a person may be capable of some decisions but not others. The SDM is then consulted to provide or refuse consent to treatment on behalf of the incapable person.
The best way to ensure an autistic adult's preferences are respected is to create a power of attorney (POA) for personal care while they have capacity. The POA allows the person to choose who will make decisions for them if they become incapable. It can include specific instructions about medical treatments, living arrangements, and personal care preferences.
Substitute decision-making in Ontario is triggered when a health practitioner determines that a person is incapable of making a specific treatment decision. This is decision-specific — a person may be capable of some decisions but not others. The SDM is then consulted to provide or refuse consent to treatment on behalf of the incapable person.
The SDM must follow the person's prior capable wishes if these are known. If prior wishes are not known, the SDM must act in the person's best interests, considering: the values and beliefs the person held when capable, their current wishes (even if incapable), whether the proposed treatment will improve their condition, and whether the benefit outweighs the risk.
The best way to ensure an autistic adult's preferences are respected is to create a power of attorney (POA) for personal care while they have capacity. The POA allows the person to choose who will make decisions for them if they become incapable. It can include specific instructions about medical treatments, living arrangements, and personal care preferences.
A POA for personal care can be created by any adult with the capacity to understand its nature and effect. Many autistic adults have this capacity. Work with a lawyer to create the document. Include detailed instructions about the person's preferences, values, and prior wishes to guide future decision-making. Review and update the POA periodically.
HCCA
Health Care Consent Act, S.O. 1996, c. 2, Schedule A — Substitute Decision-Making Provisions
SDA
Substitute Decisions Act, S.O. 1992, c. 30 — Power of Attorney for Personal Care
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Commitment to Accuracy: Our data is verified against official government reports (FAO, MCCSS), peer-reviewed scientific literature, and accessible public records. Last updated: March 24, 2026.
Written by Spencer Carroll
Founder & Autism Advocate