How to Be Friends With Your Sibling

That may be an extreme example of carving out time for each other. But, Ms. Goodman said, siblings sometimes lose sight of the fact that their relationship, like any other, requires attention and care. “We often expect family relationships to thrive simply because someone is related to us, but it doesn’t work like that,” she said.

Siblings should find ways to have fun together, Dr. Kramer said. “It’s really hard when all your interactions are about problems one of you is having,” or when you are arguing about who is going to take care of a parent’s needs, she said. “Find moments where you can really enjoy one another.”

Sometimes, it is enough to take out old photos and spend a few minutes reminiscing, Dr. Kramer added.

The LoCicero brothers relished race days, and how they were often able to bring their wives and children along and make a weekend out of it. But they savored the hours they spent training and planning together just as much. Sometimes they ran in silence. Other times, they talked about work, marriage and kids. (The LoCiceros also have a sister with whom they are good friends and a brother who died from pancreatic cancer 15 years ago, a painful loss that brought them even closer.)

Even though their 50-marathon quest has been completed, the brothers still talk on the phone or see each other every few days, and live only seven miles apart. “Kenny, I know, is always going to be available, accessible, willing to listen,” Ricky said. And he believes there is nothing that could change that bond.

“With Ricky, there’s nothing I would not say out loud,” echoed Ken. To know how committed his brother is to their relationship, and to feel that they can be honest and vulnerable with each other is, he said, “a gift.”