Billionaire Sumner Redstone controls a media empire that still broadcasts soap operas like those from the dawn of TV. Starting Friday, the fading mogul’s own saga will spill out in a Los Angeles courtroom like one of those serial dramas: with spurned lovers, a contested will and questions of who’s in charge.

Redstone, 92, who controls Viacom Inc. and CBS Corp., is facing trial over whether he was mentally competent when he threw ex-girlfriend Manuela Herzer out of his home in October and removed her from overseeing his medical care. Besides exposing his frailty, including difficulty speaking and eating, the case will spotlight Redstone’s fraught relations with his family and the millions he’s lavished on women around him.

The verdict could decide who ends up controlling Redstone’s stake in Viacom and CBS, media giants worth $42 billion. While Redstone stepped down as chairman of both in February, he still holds majority voting rights through a family holding company, National Amusements Inc. If he’s found incompetent, NAI’s board, including his daughter Shari Redstone and Viacom Chief Executive Philippe Dauman, might step in.

“The trial will expose the tragic inconvenient truth that Sumner Redstone needs the court’s protection from those who have lied to and exploited him in his debilitated condition,” Pierce O’Donnell, Herzer’s attorney, said Thursday in a statement.

The parade of witnesses set to testify about Redstone’s mental health and the alleged plotting and scheming by those around him include ex-girlfriends, geriatric psychiatrists and Redstone’s own nurses. Others will include Shari, with whom he has had a rocky relationship, a granddaughter who claims Redstone needs court protection from his own daughter, and Dauman.

Absent from the courtroom will be Redstone himself. Los Angeles Superior Court Judge David Cowan, while acknowledging the aging billionaire is the most important witness, agreed to let him testify via a videotape that won’t be shown in open court.

Manipulation Claim

Cowan ruled Thursday he won’t split the trial in two, saying he’ll consider whether Redstone was competent when he removed Herzer from her health-care role, as well as whether the media patriarch was manipulated into turning over control of his medical care to Dauman.

Herzer, the former girlfriend, filed a petition in November to have a probate judge declare Redstone incompetent and have her reinstated as his health-care agent -- the individual empowered to make decisions when an elderly or ill person can’t. Redstone’s lawyers accuse Herzer of being more concerned about his money than his health, because he cut her out of his will at the same time he removed her as his health-care proxy.

In a court filing this week, Redstone’s lawyers said that in the weeks before she was evicted, Herzer spent more than $200,000 using Redstone’s American Express card and had him sign for $40,000 in cash delivered to his house. She executed a $5 million grant agreement with Redstone for her foundation, they said.