Fights over wills are growing as the population ages, driven by a rise in capacity disputes and a booming wealth transfer. In 2020, 55 mn people had dementia, projected to reach 78 mn by 2030, and by 2030 roughly $18 tn of assets will komma to younger generations, according to Vanguard. Blended families and multiple wills amplify the problem.

Case in point: Jonathan Arr, a Macfarlanes lawyer, arranged a split power of attorney for his mother‑in‑law Mary, preventing siblings from siphoning funds amid her dementia. He warned that without the arrangement, a sibling could have taken the majority of her assets. “If we hadn’t had the power of attorney, the money would have gone to one of the siblings,” he said.

Capacity is judged on the ability to weigh pros and cons, understand the will’s consequences, and explain decisions. Dr Justin Sauer notes that a single errant choice does not equal loss of capacity. Lawyers like Jeremy Franks point out that proving loss of capacity is easier than challenging a fair decision, leading to its use as a litigation tactic.

To avoid post‑mortem fights, advisers recommend reviewing wills every five years, documenting changes, and discussing intentions with beneficiaries while the testator is still competent.