Previously the Court has been prepared to infer undue influence from certain extraneous factors. Not any more, at this stage. So beware caveating the will drawn at the request of a sibling by the siblings lawyer when some signs of dementia were evident. It may go to testamentary capacity but it won't clear the bar for coercion.
The 2017 Court of Appeal case of Montalto v Sala was an appeal from a decision of her Honour Justice McMillan striking out particular off undue influence by a caveator. The facts were alarming, at least to the writer, and would normally have been sufficient to displace the burden of proof. Justice McMillan found otherwise and struck out the particulars as inadequate. The Court of Appeal upheld the trial judges finding. See Re Montalto  VSC 266,