Rob and Michele Reiner’s eldest son Jake wrote an essay about the “living nightmare” of their murders, for which his younger brother Nick stands accused.

Nick, 32, has pleaded not guilty to two counts of first-degree in the Dec. 14 slayings, for which he could face life in prison without the possibility of parole or the death penalty.

In a Substack essay published Friday, entitled, “Mom and Dad,” 34-year-old Jake hoped to “offer some insight … to what I lost but also to celebrate what my parents meant to me.” He prefaced that sister Romy, 28, “will tell hers in her own way and in her time.”

He recounted learning about their deaths while at a celebration of life for a recently deceased best friend. Romy, who reportedly discovered their parents’ bodies, called to notify Jake that “our father was dead” and called back “minutes later … telling me our mother was also dead.”

“My world, as I knew it, had collapsed. … I was robbed of so many things that day,” said Jake, who along with Romy “lost more than half of our family that night in the most violent way imaginable.”

The dual tragedy “simultaneously breaks my heart and enrages me” and is “too devastating to comprehend,” said Jake.

He said he continually wakes up “having to convince myself that, no, it’s not a dream. This truly is my living nightmare. … Every day since then has been horrendous.”

“Any loss of a parent is devastating, but nothing compares to losing both of them at the same time and, on top of that, having your brother be at the center of it,” wrote Jake. “It’s almost too impossible to process.”

While he said some questions about the case will be answered “in time,” others “parts of this belong only to our family, and keeping them private is the only way to protect what little remains of something that was taken from us.”

Jake said his parents “were the last people in the world to deserve what happened to them” and pointed to their “truly unconditional” love for all three children, as well as their “love … for each other,” which he always “looked up to.”

“To me, my parents are at the center of my life. … A lot of people don’t have the luxury of having the best parents, the best mom or the best dad, but I did,” he said.

Jake remembered Michele as his confidante, and he hers. She was “the engine, the backbone, and the heart of our entire family.” Rob, he said, “is my hero” with whom he “could talk … about anything. No subject was ever off-limits.” Jake said he misses both “so much.”

He ascribed his “intolerance to bulls–t” to his “sensitive” and “really funny” mother, with whom he would regularly see musicals. He recounted the annual baseball trips he’d take with his dad — the same “beautiful person” at home that he was in public — and their mutual devotion to the Los Angeles Dodgers.

Jake acknowledged such experiences were possible due to his parents’ prominence, all of which he’d “trade … if I could just spend just one more hour talking to them and to say goodbye.”