My daughter Norah is 5 years old today. We have gifts and balloons and a cake for her — just like we did when she turned 1, 2, 3 and 4.

This year, though, we have a new member of our family who'll be joining us in celebrating another year around the sun for our joyful and kind-hearted girl.

One year ago, Norah exclaimed, "Hi, old person! It's my birfday today!" to an elderly man in a grocery store. Her brutally honest words, which mortified me at the time, were the same ones that allowed us to meet, befriend, and now love Dan Peterson as if he's always been part of our family.

After learning that he had been recently widowed, I arranged a lunch date with "Mr. Dan" that following week. You'd never have known that he and Norah had met only once before — they talked and laughed and enjoyed each other's company like old war buddies. They had a connection that I didn't quite understand but knew I couldn't forsake. We made a plan to get together the next week, too. When Norah asked if we could visit Dan every week, I agreed without hesitation. Who am I to stand in the way of fate?

Norah, my 2-year-old daughter Marigold and I have visited Dan in his home every single week for the past year (save for once when Norah was sick and once when I was out of town). He has a small child-sized table permanently set up in his den with crayons, puzzles, and dollar store novelties for the girls. He keeps juice pouches and snacks at the ready for when we come over. He even cleared out space in his refrigerator for me to keep a six-pack of Diet Coke — that's just one of the many ways I know he loves me as I love him.

When he met Marigold, she had just turned 1 and wasn't yet walking. She now tears through his house like a whirling dervish and never stops talking or asking him questions. At every visit, she climbs into his lap so she can reach the calculator on his side table which she pretends is a cell phone. You'll find her using his broom and dust pan to sweep up the plastic wrappers she dropped on the floor that covered the caramels she shoved in her mouth — the caramels that Dan keeps in a basket on the counter just for my girls. He is patient and kind and entertained by her. He loves her almost as much as he loves Norah.

At least twice a week, Marigold will ask, "We see Dan today?" and if I say, "No, not today" she asks, "Why not?" and then I ask myself, "Why not" and if I have nothing pressing planned, we'll pop in for a 20-minute impromptu visit. We leave there all smiley-faced and happier than we were only minutes before. Spending time with people you love tends to do that to you.

And it's not just my little girls who adore Dan — he's joined us in our home for Thanksgiving and for birthday parties for several of my other kids. They scramble to greet him at the door and elbow each other out of the way to be the one who gets to serve Mr. Dan his slice of cake. At one party, my 7-year-old Ronan, who sees little to no value in other human beings outside of the people who live in our house, sat with Dan on our couch and they shared a plate of cheese puffs. He put his arm around Dan and laid his head on his shoulder. Like, I took pictures because I have never seen my son so comfortable with a (at the time) near-stranger and I've certainly never seen him voluntarily share cheese puffs. It stopped me in my tracks and was just another clue to me that Dan was, indeed, becoming family.

Over the past year, Dan has also become one of my best friends. He regales me with anecdotes of his childhood on a ranch and his years as a mathematics professor, a pilot, an auctioneer, a husband, a father. I'm astounded by his sharp memory and recollection of details, names, dates and places. When we're really supposed to be there for the girls to visit with him, I find myself "shushing" them so I might better hear his stories and soak in his words. He knows something about everything and I never grow tired of learning from him. We talk a lot. We laugh even more. We always say we love one another when our visits end.

I didn't expect our relationship with Mr. Dan to evolve the way it has, but the universe has a way of gifting us with people we didn't know we needed until we can't imagine life without them. Sometimes those 'people gifts' become your family.

I needn't share DNA with Dan to love him and know he loves us as each other's flesh and blood. I can feel it in his hugs and I can see it in his eyes and smile.

Love and devotion are what define "family" to me — whether you're born into it or you unexpectedly meet it in a grocery store.