In their explosive lawsuit filed Thursday, Tom Benson’s heirs — daughter, Renee Benson and grandchildren Rita and Ryan LeBlanc — describe the Saints owner as tottering on the brink of senility, being manipulated by his wife and demonstrating “bizarre” behavior. They’ve asked a judge to appoint Renee to oversee his business affairs.

But persuading a judge that such action is necessary, as their suit requests, won’t be easy, experts said.

“There are hundreds of these cases each year, and only a handful move forward,” said Ronald Scalise Jr., vice dean for academic affairs and A.D. Freeman professor of civil law at Tulane University. “It’s very difficult to prove.”

To bolster their request to have Benson declared incapacitated, his heirs say in their suit that the family patriarch has memory lapses and has confessed to having “difficulty thinking.” The lawsuit also says he has appeared disoriented and often slurs his speech and forgets details like the birthday of his daughter and the name of the current president.

Those anecdotes alone, however, won’t be enough for a judge to find him incompetent, said Nikolaos Davrados, a visiting professor at Loyola Law School who specializes in civil law.

Judge Kern Reese, to whom the case has been assigned, will be listening for testimony from medical experts with evidence that Benson suffers from “certain diseases” that would render him “disabled mentally,” Davrados said.

His family will have to prove that he “doesn’t have a connection with reality” or that he “cannot clearly take care of himself mentally or physically,” Davrados said. “The burden of proof is particularly high.”

In Louisiana, a person can be declared mentally unfit at the conclusion of a court proceeding called an interdiction hearing. Such hearings can include testimony from relatives and experts and other evidence demonstrating that an individual is or is not capable of consistently making sound decisions about himself, his property or some part of either. If a person is found to be incapable, the court names a curator to make some or all decisions on his or her behalf.

Interdiction, also known as guardianship or conservatorship, often is sought by the children or other close relatives of elderly individuals, but it also can be applied to people of any age who are believed to be incapacitated, for reasons ranging from substance abuse to mental illness.

Requests for interdiction are “not uncommon when large amounts of money are involved and blended families are involved,” Scalise said. The Benson family dispute pits Benson and his third wife against the daughter of his first wife, now deceased, and her two children.

Benson’s now-estranged relatives asked for the interdiction in a petition filed Thursday in Civil District Court. A hearing date has not yet been set.

The request was filed in response to Benson’s announcement Wednesday evening that he plans to leave his NFL and NBA teams, as well as other business holdings, to his wife, Gayle, upon his death. The decision cuts out his granddaughter, Rita LeBlanc, who had been heir apparent, and LeBlanc’s mother and brother, who ran other portions of Benson’s business empire.

Benson, in a statement issued Thursday, called allegations that he was of declining mental health “completely meritless.”

“I will vigorously defend my decisions and the businesses I have built,” Benson said. “The false accusations in this suit further support the actions I have taken in changing the succession and transfer of ownership.”

In a brief televised interview Friday with WVUE-TV, which he owns, the 87-year-old Benson said he felt “great. Just like a 50-year-old.”

But his heirs believe that determination should be made by an independent geriatric psychiatrist. Their thinking, apparently, is that an evaluation might reveal some level of dementia and therefore a lack of capacity to make any of the changes he has announced, said Dr. Robert Abrams, a general and geriatric psychiatrist and professor at Weill Cornell Medical College.

Such an exam, if one is ordered, would evaluate Benson’s cognitive status — his orientation, memory, abstract thinking, problem-solving and other faculties, Abrams said. It also would consider whether mood symptoms, like depression, and a lack of logical, rational reasoning were clouding his judgment.

Benson’s attorneys will likely try to prevent any such exam on the grounds that it is unnecessary or that the family lacks the standing to make such a request, Abrams said.

“Sometimes in these situations, if there is a great deal at stake, each side arranges for a geriatric psychiatrist and there are dueling experts,” Abrams said.

If the case proceeds to trial, the judge could either reject the relatives’ request or impose a full or limited interdiction, Davrados said. In a full interdiction, a curator would be assigned to make all decisions for the person found to be incapable. In a limited interdiction, the curator would make only the decisions decided by a judge. For instance, the interdicted party could be allowed to pick his own doctors but not to decide how his money is invested.

Benson’s heirs have asked that his daughter, Renee Benson, be named curator. If one is appointed, they will likely argue strongly that it should not be Gayle Benson, which would require them to persuade the judge that Benson is not only prone to manipulation but that Gayle has “undue influence” on him, Scalise said.

He said that would be a high burden to meet.

“Undue influence is slippery and difficult to confine,” Scalise said. “You would have to show that someone has substituted their volition for yours, so that even though you wrote the will, it wasn’t really what you wanted and they had a special level of influence over you to do so.”

Reese, the judge overseeing the case, is no stranger to messy, high-profile family squabbles. He oversaw a similar dispute between Barry Kern and his father, Blaine Kern, “Mr. Mardi Gras,” about the ownership of the family’s Carnival float empire in 2011.

In that case, Barry Kern sued his father after Blaine Kern refused to comply with an agreement handing over a majority stake in the company. Barry Kern said the company was in a “fiscal crisis” due in large part to Blaine Kern’s fourth wife, Holly Brown-Kern, whose entrance into the family coincided with a spike in spending.

In that case, the younger Kern was not attempting to have his father found mentally unfit. But Blaine Kern, then 84, argued that his decision to turn the company over to his son should be thrown out because it was made while he was under duress, facing pressure from his son and the heads of some prominent parading Carnival organizations.

Reese ruled in favor of Barry Kern, saying he didn’t buy Blaine Kern’s claim that he was bullied into signing over his company. Barry Kern was represented in that case by Randy Smith, who is now representing Rita LeBlanc.