To draft an estate plan, a person must have testamentary capacity. This is the mental capacity to understand the estate planning process, to fully grasp the decisions that they are making and things of this nature. A person just needs to be cognitively aware of the impact of their estate plan on themselves and their beneficiaries.
One important thing to remember is that the law presumes testamentary capacity. If someone makes an estate plan, the starting point is the assumption that they had the mental capacity to do so and that the document should stand.
When this comes into question is when someone challenges it. A beneficiary may claim that a person lacked testamentary capacity to make alterations to their estate plan late in life, for instance. The burden of proof is then on that person to demonstrate the loss of testamentary capacity.
How could someone lose this capacity?
Illnesses, especially degenerative brain diseases, are commonly cited in these cases. If a person wrote a will, but beneficiaries claim they had dementia or Alzheimer’s, for instance, it could call their testamentary capacity into question. The same could also be true for certain injuries, like a traumatic brain injury.
In some cases, drug or alcohol use could play a role. If someone was a known drug addict before they passed away, beneficiaries may believe that an estate plan was written while under the influence of these substances. That, too, could mean the person lacked the capacity to draft these legal documents and did not fully understand the ramifications.
These are certainly very complex cases, and it is important for those involved to understand all their legal options.

