Everything depends on the intention of the parent. Did the parent need his child’s help to manage finances and really want the money to be distributed in accordance with the instructions set out in the Will or did he want the joint account holder to receive the money?
The court will examine the evidence and make the determination accordingly. If the evidence is unclear the court will presume that the surviving joint account holder is holding the money in the joint bank account in trust for the estate. This is called a Resulting Trust.