I turned to my 91-year-old grandfather for advice before starting a business with my brother. He said to leave ego out of it.

This as-told-to essay is based on a conversation with Nathan Bennett, co-founder of Crux Analytics. It has been edited for length and clarity.

When my brother started asking me more and more questions about the financial technology company he wanted to start, I could see where things were heading.

Jacob’s great with big ideas, and he had identified a problem in the market. He needed my engineering expertise to make his solution a reality.

One day, about three years ago, Jacob asked me to read his pitch deck for accuracy. The last slide was the team. There was Jacob, and next to him was my name. Under my bio, it said something along the lines of “Nathan knows he wants to jump ship from his job to work with his brother.”

Jacob was right; we’d always had a dream of building something together. But I’ve always been the more cautious brother. Leaving my well-established career in medical devices felt risky. So, I reached out to our grandfather, Michael, to help me make the decision.

My grandpa is in his 90s and still working with his brother

Michael has been in business with his own brother, Maurice, for more than 70 years. Today they’re 91 and 93, and they still work together. Most of their career has been in women’s fashion, and more recently in men’s shoes.

I told my grandfather to give me the good, the bad, and the ugly of working with your brother. I knew that if a startup didn’t work out, I had other career options I could fall back on.

But I worried that being in business together might alter the great sibling dynamic that Jacob and I have.

We each have our own skillset

My grandfather said he and Maurice had different areas of expertise and different strengths, so they were never trying to prove anything to each other. No one had to assert dominance because they each filled different niches.

Like Michael and Maurice, Jacob and I have very different skill sets. Jacob’s got the big ideas, and I’m the planner. If we were on a hike, Jacob would just start walking and figure it out, while I would analyze every possible route.

Jacob jokes we’re like the Transformer toys that were popular when we were growing up in the 90s. We each have our own superpowers, but when you put us together, we become something even stronger.

We’re intentional in how we talk about each other

Our grandfather had another piece of advice. He and our grandfather are very close with Maurice and his wife; they even live within walking distance of each other.

When Michael and Maurice started in business together, our grandfather told our grandmother that the friendship between the couples was always going to come first.

Sometimes, that meant my grandfather didn’t tell my grandmother everything that happened during his day. He never wanted a little tiff at work or disagreement to cloud his wife’s ideas about Maurice.

That’s an example Jacob and I follow. We’re very careful about how we talk about each other and the business with other family members.

Business has kept our family close

Being in business with my brother, I know with absolute certainty, all the time, that Jacob has my best interest at heart. There’s almost a telepathic connection between us, and a lot that doesn’t need to be said.

Partnerships with friends or co-founders might come close, but they don’t have that same foundation that we’ve been building since Jacob was born.

Because our grandfather is in business with his brother, our families have been extremely close. When I called my grandfather that day, he emphasized that above all else, working with his brother has been fun and rewarding.

That’s the legacy Jacob and I hope to carry on.