Ask HN: Starting a startup with a sibling: how to not destroy our relationship?

I am planning to co-found a startup with my brother. We will be bootstrapping. The business is not capital intensive.

I heard of enough stories how relatives or close friends lose the relationship due to some quarrel in the business. Which questions should we ask (and answer!) ourselves before we endeavor into this? First and foremost, we want to avoid situations that can be avoided that can lead into an irreversible conflict.

Both anecdotes (I did X and it caused Y, and it was great/awful) and general advice would be appreciated.

Thank you!