The lawsuit accused Lisa Marie's former business manager, Barry Siegel, of acting negligently with her money and allowing Priscilla's high salary.
Priscilla recently contested a 2016 amendment to Lisa Marie's trust, which removed her and Siegel as trustees and replaced them with Riley and Benjamin Keough.
Priscilla wrote a loving message on what would have been Lisa Marie's 55th birthday, expressing her desire to keep the family together.