Sumner Redstone is the 92-year-old media mogul who controls Viacom Inc. and CBS Corp.  The trial will focus on whether Redstone knowingly kicked out Manuela Herzer, a former girlfriend and longtime companion, from his mansion in October, and whether he was competent to remove her as Agent under his Health Care Power of Attorney.

Redstone had planned to leave his former companion Manuela Herzer $50 million and his Beverly Park mansion in Los Angeles that is worth about $20 million, but that was before he removed her from his estate plan in October. Those assets now are designated to go to Mr. Redstone’s charitable foundation after his death.

Mr. Redstone changed his estate plan on the same day he removed Ms. Herzer from an advance health care directive that would have put her in charge of his health decisions. In November 2015, Ms. Herzer filed a suit claiming that Mr. Redstone lacked the mental capacity to remove her from the health directive.

The legal dispute is personal but the outcome of the suit, including any finding about Mr. Redstone’s mental competence, could have implications for his controlling stake in Viacom and CBS.

Mr. Redstone’s lawyers have called the suit “meritless” and have claimed that Ms. Herzer, a former romantic partner, was after his money. “This is a pre-death trust contest dressed up as health care litigation,” lawyers for Mr. Redstone stated in the court documents. Redstone’s daughter revealed in a court filing last week that Ms. Herzer had received more than $70 million in cash and assets from him since 2009.

Ms. Herzer’s lawyer has said in a statement that his client’s sole concern was Mr. Redstone’s well-being. “The only reason Manuela is fighting this fight is out of concern for Sumner’s well-being and a desire to honor the decisions he made when he was competent to do so,” he said. “The fact is that she is one of the only people around Sumner who has consistently put his interests first, which is why they regard her as such a thorn in their side,” Mr. O’Donnell added.

Mr. Redstone resigned as executive chairman of Viacom and CBS after investors and analysts raised questions, prompted by Ms. Herzer’s lawsuit.

This case, while high profile, is demonstrative of issues we regularly address in Arizona involving allegations of an individual’s capacity to change estate planning documents, make medical decisions and/or handle financial matters. We will keep you posted on the Sumner Redstone case from California.