Research studies indicate that up to 45 percent of adult siblings have relationships marked by rivalry or distance. A story from the Wall Street Journal featured Al Golden, 85, who still chokes up when he talks about his twin brother, Elliott, who died three years ago. The brothers shared a room growing up in Brooklyn, N.Y., graduated from the same college and then married within a month of each other in 1947.

Yet Mr. Golden still remembers how their father often compared their grades, asking one or the other, "How come you got a B and your brother got an A?" Elliott Golden became a lawyer and eventually a state Supreme Court judge. Al Golden went into the mirror business then sold life insurance. He says he always envied his brother's status and secretly took pleasure in knowing he was a better fisherman and owned a big boat. Once, Elliott asked him, "I am a lawyer. How come you make more money than me?" Mr. Golden says. "He meant: 'How come you are making more than me when you are not as successful?' But it made me feel good."

One day, Elliott accused him of not doing enough to take care of their ailing mother. After the conversation, Al didn't speak to his brother for more than a year. "It might have been the built-up of jealousies over the years," he says. His brother repeatedly reached out to him, as did his nieces and nephews, but Mr. Golden ignored them.

Then one day Al received an email from his brother telling a story about two men who had a stream dividing their properties. One man hired a carpenter to build a fence along the stream, but the carpenter built a bridge by mistake. Mr. Golden thought about the email then wrote back, "I'd like to walk over the bridge." "I missed him," Mr. Golden says now. "I never had the chance to miss him before."