LKY's Wills were made between August 2011 and December 2013 before he died in March 2015.
He developed Parkinsons sometime in March 2012, about seven months after his first Will. His initials after Para 7 of his final Will (Dec 2013) do not show the jagged and squiggly nature of someone in an advanced stage of the disease. Also, the cognitive disorders associated with Parkinsons trail behind the movement disorders during the early stages of the disease. Hence, LKY would have suffered from "mild cognitive impairment" at the most and worse, if at all, when he signed his last will in December 2013. He was still in control of his mental faculties during this period. This is borne out by his meetings with world leaders and the activities he continued to participate in at grassroots level during this March 2012 to December 2013 period.
As such, it is unlikely that he changed his mind due to the disease. From all the info available so far, it's reasonable to conclude that he made the changes in his attempt to find a way to circumvent his first born's determined plan to thwart his and his wife's wish to have their house demolished.
