The couple arrived at O’Brien’s party with Nick in tow. They’d asked if he could come along because they were worried about him. After battling drug addiction for years, apparently beating it and then relapsing hard, he’d moved into their guesthouse. Some reports suggest he’d recently been prescribed medication to treat schizophrenia, others that he had been on methamphetamine benders, punching holes in walls. The couple were alarmed enough to ask for a plus-one. • Nick Reiner: who is the man accused of killing his parents? O’Brien’s estate is near the beach in the Pacific Palisades, walking distance from Brentwood....