Capacity To Sign A Will. Who Decides?
A Faltering Memory And The Viability Of A Will
A will-maker must have the capacity to appreciate and understand the nature and extent of his or her property being disposed of, the persons who are the natural objects of his or her estate, and the testamentary provisions he or she is making. A will-maker must possess this capacity when he or she gives Will instructions and when he or she executes a Will. Therefore, authorities permit a compromised will-maker to execute a Will during a lucid interval, and that Will may still be valid, despite a will-maker’s faltering mental capacity.
Laszlo v Lawton, 2013 BCSC 305
In this case, the plaintiffs were the deceased’s nieces and nephews whom had made an application to the court to challenge the validity of the deceased’s last will and testament on the grounds that she lacked testamentary capacity. During the 2 years prior to the preparation and execution of her Will, the deceased had experienced numerous episodes of confusion, paranoia, delusions and ongoing cognitive deterioration, which ultimately led to a diagnosis of severe dementia in the years after the execution of her Will. This was supported by medical evidence at trial from the doctors who examined and/or assisted the deceased, as well as testimony from the plaintiffs and lay witnesses regarding their observations and interactions with the deceased. In conclusion, the court determined that the deceased lacked testamentary capacity when she gave instructions for the preparation of her Will and at the time she signed it.
The Test for Testamentary Capacity
Re Schwartz (1970), 10 DLR (3d) 15 at 32 (Ont CA) established the following test for testamentary capacity.
The testator must be sufficiently clear in his understanding and memory to know, on his own, and in a general way:
1. the nature and extent of his property;
2. the persons who are the natural objects of his bounty; and
3. The testamentary provisions he is making; and he must, moreover, be capable of
4. appreciating these factors in relation to each other; and
5. forming an orderly desire as to the disposition of his property.
 The issue of whether a testator has the requisite capacity to make a will is a question of fact to be determined in all of the circumstances: Knox v. Trudeau 2001, 38 E.T.R. (2d) 67 (Ont. Sup. Ct. J.). The assessment is a highly individualized and fact-specific inquiry. As most cases are unique on their facts, appellate courts will not overturn a finding as to capacity unless the trial judge has made a palpable and overriding error: James v. Field, 2001 BCCA 267 at para. 71 [James].
 Testamentary capacity is not a medical concept or diagnosis; it is a legal construct. Accordingly, scientific or medical evidence – while important and relevant – is neither essential nor conclusive in determining its presence or absence. Indeed, the evidence of lay witnesses often figures prominently in the analysis. Where both categories of evidence are adduced, it is open to the court to accord greater weight to the lay evidence than to the medical evidence, or reject the medical evidence altogether: Baker Estate v. Myhre (1995), 28 Alta. L.R. (3d) 428 at para. 39 (Q.B.); O’Neil v. Brown Estate,  S.C.R.
622 [O’Neil]; Spence v. Price (1945),  2 D.L.R. 592 at 595-96 (Ont. C.A.); James at para. 77; Miliwat v. Gagné, 2009 BCSC 1447, aff’d 2010 BCCA 323 [Miliwat].
Timing is Key
Two relevant times when a testator must have testamentary capacity:
1. when he or she gives Will instructions; and
2. when he or she executes the Will.
The court recognizes that faltering mental capacity is prone to fluctuate, therefore the authorities permit variation of the degree of capacity required at these pivotal times. For example, if a testator was competent to give Will instructions but loses capacity at the time of execution, the Will may be valid if the testator has the capacity to understand that he or she is executing a Will prepared in accordance with his or her previous instructions: Parker v Felgate (1883), 8 PD 171; Brownhill Estate (1986), 72 NSR (2d) 181 (Co Ct).
 To lack testamentary capacity does not mean that the testator must be in a perpetual state of substandard competence. Seemingly rational persons may be without it, while seemingly compromised persons may possess it. A testatrix’s cognitive and psychological state is amorphous and seldom static. It may change and fluctuate slightly or wildly, such that at times she is not of sound mind, while at other times she is perfectly lucid. Accordingly, a will made by a compromised testatrix executed during a lucid interval may still be valid.