Can I still update my will if my health or memory is declining in Ontario?

Yes — but whether you can depends on whether you have testamentary capacity at the time you sign the update, not on your general health. A person can have a significant medical condition, including early-stage dementia or other cognitive impairment, and still retain testamentary capacity on a particular day if they understand what they own, who their heirs are, what the will does, and how it all fits together.

Capacity is assessed at the moment of signing, and it can fluctuate. A person who lacks capacity in the morning may have a clearer interval in the afternoon. This is why timing and documentation matter enormously when health is declining.

If you are concerned about whether your capacity may be questioned, there are steps that help protect the will from later challenge. A lawyer can administer a careful capacity assessment and take notes at the meeting. A contemporaneous letter from your physician confirming your capacity at the relevant time is also valuable. The lawyer should keep a record of the questions you answered and the understanding you demonstrated.

Acting sooner rather than later is the wisest course. Once capacity is genuinely lost, you can no longer make or update your will, and a court-managed guardianship process would govern your affairs instead.