We don't know the whole story.
He is willing to invest his money into a foundation, assumably for good causes; So that implies he is smart, and he is generous, at least on some level.
Maybe his sister doesn't need his charity. Or maybe he has already disowned his sister for some other valid reason.
In any event, it's his money, and if he were to give money away like that what would keep people from constantly coming back to him for more?
edit: yeah, what UW says too.
