Rob Reiner’s estimated $200million fortune has become the focus of intense scrutiny, with sources telling RadarOnline.com a significant portion of the late director’s estate is being used to fund the high-powered legal defense of his son Nick Reiner, who stands accused of murdering his parents.

The financial questions surfaced this week outside Los Angeles Superior Court, where Nick, 32, appeared for the first time, charged with two counts of first-degree murder in the deaths of Rob, 78, and his wife, Michele Singer, 68.

Nick’s attorney, Alan Jackson, a veteran criminal defense lawyer known for representing figures including Phil Spector, Harvey Weinstein, and Kevin Spacey, declined to say who was paying his fees, which can run to at least $2,000-per-hour.

A source, however, told us the money is coming from Rob and Michele’s estate.

“Despite their massive trauma, rage, and grief, the family decided that money from the estate should go toward ensuring Nick has the most robust defense available,” the insider claimed.

“They feel a secure mental health institution would be a better outcome than him spending his life behind bars. And they know it is what Rob would have wanted.”

Nick appeared in court on Wednesday wearing what appeared to be a suicide-prevention vest, his wrists shackled, after his arraignment was delayed for medical reasons.

A lifelong family friend said Nick’s mental health struggles predated his years of rampant drug use and shaped family decisions for years.

“He had serious issues well before drugs became part of his life,” the source said.

“When substances came into play, the situation escalated dramatically, but Rob and Michele continued to do everything they could to support him.”

The insider added that there were episodes of aggression.

“At times the family felt genuinely afraid,” the source claimed. “Michele would often say, ‘I don’t know what more we can do.'”

Rob and Michele were found dead in their Brentwood home in the early hours of Sunday, December 14, hours after attending a holiday party hosted by Conan O’Brien.

It’s understood the couple had their throats slashed while in their bed. Nick waived his right to enter a plea in court, and no motive has been established.

Under California’s “Slayer Statute,” a person convicted of killing another is barred from inheriting from the victim.

Even so, relatives can contribute funds for legal expenses, and the Reiner estate is substantial.

Rob and Michele, married in 1989, shared three children – Jake, 34, Nick, and Romy, 28. Rob also had an adopted daughter, Tracy Reiner, 61, from his marriage to Penny Marshall.

The couple’s assets include a six-bedroom Brentwood mansion, now valued at more than $13million, which was originally built by Henry Fonda, and a Malibu beach house estimated at $15million.

Rob also inherited wealth from his father, Carl Reiner, the creator of The Dick Van Dyke Show.

But his own success – particularly with films such as When Harry Met Sally – and the founding of Castle Rock Entertainment, producer of Seinfeld, generated the bulk of the massive family fortune.

According to his friends, the Hollywood star was ambivalent about wealth.

“He was concerned his children might grow up under his shadow, as he had,” a second family source claimed. “For years, he made clear that a significant portion of his wealth was destined for charitable causes.”

The source added: “The children will receive substantial inheritances, but giving to charity was always a core part of Rob and Michele’s vision.”

Rob was a prominent activist, backing early childhood education through Proposition 10 and later campaigning for marriage equality.

Former Los Angeles mayor Karen Bass said Reiner “always” used his gifts in “service of others,” while Jane Fonda described Rob and Michele as “wonderful, caring, smart, funny, generous people.”

Rob Reiner was astonishingly living in what friends tell RadarOnline.com was an oasis of calm in a home that felt entirely fear-free in the weeks before the Hollywood director and his wife Michele were killed in a sudden explosion of brutality that has stunned the world.

There was not a sign of the violence to come, according to a source close to the family.

Other sources close to the family echoed the description of the house as calm and welcoming, saying Rob and his wife had spent years trying to support their son through addiction while maintaining a stable, open home.

One family friend said the residence felt like a “refuge, not a fortress,” while another neighbor described it as “quiet, normal and totally unguarded.”

Nick Reiner was formally charged on Tuesday, December 16, with two counts of first-degree murder.

If convicted, the self-confessed drug addict could face life in prison without parole or the death penalty.

Los Angeles County District Attorney Nathan Hochman stated: “He also faces a special allegation that he personally used a dangerous weapon, that being a knife.”

Police say Rob and Michele Reiner, 68, were found with their throats slit in their mansion on Sunday, December 14.

Their daughter Romy Reiner, 28, who lives across the street, discovered the horrific scene.

Nick was arrested later that day at a downtown intersection near USC, about 15 miles away.

He was taken into custody without incident.

Bystander Kevin Cheatham, 34, said Nick appeared calm as officers moved in.

Barry, who is deep in grief over the slaughter, added: “I can’t believe they’re not here. [Rob] was like my family. Four, five days later, I’m here in this f—— nightmare.”