The Extended Family should try to maximize wealth across the entire family, instead of maximizing the wealth of some of the individuals.
I think they call that socialism.
But if someone in a family hits it big and they choose to help the others that’s different.
One of my kids is an aerospace engineer. Last I knew, he makes $170,000 a year. Well above that of him siblings. (And me)
Over the last couple years two of my kids had some serious car trouble. He was very quick to offer to help with an interest free loan.
None of us believe in handouts.