Many wills and trusts are challenged on the ground that the testator simply lacked the required testamentary capacity to sign a will or trust, or other legal document. Frankly, none of us need to demonstrate much in order to sign a will. Any individual can sign a will so long as they generally understand what they own, generally understand their relatives, and have a general and basic understanding of what an estate plan actually does (gives money or personal property items to individuals when one is dead).
The evidence necessary to convince a judge that an individual lacked the ability to even have these basic understandings can be significant. Sometimes expert testimony can be used. A medical doctor or a psychologist might be called to review deposition transcripts and medical documents in order to form a professional opinion as to whether, after the fact, the individual had the capacity to sign a document. Sometimes bringing an expert witness to the table is necessary. However, the strongest medical testimony comes from the treating physician who actually knew the testator, treated the testator, and had this knowledge at or around the time of the signing. Such testimony is generally far more persuasive than the “hired gun” who will review evidence many years after the fact and provide a medical opinion in somewhat of a vacuum.
