how much you do for other people depends on how much of the same genes you carry together
I don't remotely care about my cousins or extended family. We're not actually related in any practical sense. I havent seen them in 15 years, and we share grandparents I never met. They may as well be total strangers.
This is an example of nurture, not nature. Tribalism is because of the tribe we choose, not the tribe we're genetically most similar to.
How much you do for other people depends on how much of the same experiences you've had together.