Aidan O’Brien advised a client, who was the son of the late testator, in relation to the validity of his mother’s will on the basis that there was a lack of testamentary capacity.  The testator had been diagnosed with dementia some years prior to the execution of the will, which left the claimant with no legacies from the estate.  The claimant asserted that his mother had previously assured him that he would be left a sizable share of her estate and sought to challenge the will such that the intestacy rules would apply and thereby ensure he received a benefit.