"One day we were talking about other things outside and he says, 'Oh hold it right there!' and he was rushing to his house and when he came back, he said, 'I have a problem with my prostate,'" recalled Miguel Soto, who lives across the street.
"He said, 'I had surgery and now I am worse than before the surgery.'"
Another neighbor, James Lord, said Elkus mentioned Sunday that "he wasn't going to be around much longer."
"I told him, 'No Stan, you're gonna outlive me,'" Lord said.
Gilbert worked in general urology, sexual dysfunction and related surgical techniques, including vasectomies, bladder and prostate cancer, according to his biography on the website of Orange Coast Urology, which he joined in 1993.
One of his specialties involved using a laser to vaporize prostate tissue blocking the urinary tract.
The biography said Gilbert had been a stockbroker and a singer in a rock band. He had worked for 20 years at Hoag Hospital and was its former urology chief.
Jablon reported from Los Angeles. Associated Press writer Shaya Tayefe Mohajer in Newport Beach and AP researcher Rhonda Shafner in New York City contributed to this report.