In a Pennsylvania will contest alleging undue influence (the most common type of will contest), the party challenging the will must show that the deceased suffered from weakened intellect around the time of the alleged undue influence. (Other states require a similar showing, such as susceptibility to influence.)
How does someone prove the mental state of a deceased person?
One of the best ways is through medical records. Doctors and nurses routinely record the details of office visits and hospital stays, and often reflect the patient’s mental status. Medical records can also tell you whether the patient received prescription medication used for the treatment of cognitive improvements, such as Aricept, Namenda, or Exelon.
Medical records make persuasive pieces of evidence because they were made at the time of observation and come from an objective and authoritative source.
Another way to prove a person’s past mental status is through the testimony of witnesses who observed the person’s conduct. Family members, friends, neighbors, and caregivers have occasion to observe a person’s behavior on a daily basis and can give their opinion based on what they saw and heard.
Check for written communication among family members and others who saw the person frequently. Emails, text messages, notes, and letters may still exist that reflect on the person’s mental status.
These are not the only ways to prove cognitive condition of a deceased person, but they are some of the most common.