Can I Challenge a Will for Lack of Testamentary Capacity in Ontario?

Yes, you can challenge a will for lack of testamentary capacity, and the law sets out who must prove what. Before the court will require a will to be formally proved, a challenger must adduce or point to some evidence that, if accepted, would call the will's validity into question, and this is a minimal threshold.

The person propounding the will, usually the one asking the court to uphold it, has the legal burden of proving due execution, knowledge and approval, and testamentary capacity. Once due execution is proved, the law presumes knowledge, approval and capacity, so the challengers must bring evidence; if they show suspicious circumstances, the legal burden returns to the propounder.

Capacity means a sound disposing mind: understanding the nature and effect of the will, recollecting the nature and extent of the property, understanding what is being given, and remembering the people who might be expected to benefit. Undue influence is different: the burden stays on the people attacking the will, and it means outright and overpowering coercion. Medical records and the facts of each case matter, so talk to a lawyer early.