The two sides were close to a settlement last month, before talks broke down.
With the trial also focused on questions of whether Redstone was manipulated, testimony could turn to the on-again, off-again relations between Shari Redstone and her father, as well as tensions between her and Dauman, his longtime confidant.
Redstone has tussled publicly with his daughter over the years. In 2008, he told CNBC she wouldn’t succeed him atop the family empire. In 2010, also on CNBC, he recanted and said his daughter could succeed him in controlling CBS and Viacom. Last year, she wasn’t invited to Redstone’s birthday party.
Redstone’s decision to step down as chairman of both companies also exposed a rift between Shari and Dauman, even though they are allied in the current case. Shari Redstone was the lone dissenter when Viacom’s board voted to elevate Dauman to chairman.
The case is In re Advance Health Care Directive of Sumner M. Redstone, BP168725, Los Angeles County Superior Court.