I've joined a startup where I befriended everyone. It failed but we all stayed on good terms. I also had friends join some of my projects. I didn't even offer

I've joined a startup where I befriended everyone. It failed but we all stayed on good terms. I also had friends join some of my projects. I didn't even offer them a salary. We were all just working for free. None of those projects succeeded financially yet (though they're all still running years later as they're low maintenance and work very well). We're still friends and chat frequently. The key is to be fully transparent and honest about the situation and probability of success.