Just to put a personal spin on the question, based upon our specific situation.
My wife/me had the "honor" to raise a special needs child (now an adult).
While he's doing fine (living on his own, day to day without our direct help), he was always considered the "odd person" in our extended family.
For many years, he was (and still is) shunned by the rest of the family, because he is different.
When it came time to create a (Special Needs) Trust to see his needs (financially) after we are gone, the decision had to be made about the disposition of our remainder estate. Our son (under SSD income, along with income from a sheltered workshop), has no needs for any of our existing estate value.
After we're gone, the estate will continue to grow in value till his passing, and then passed on to our various charities. It projected worth? Let's just say more than a few dollars
...
Will anything be passed on to our neices/nephews? Nope. We would rather leave it to our named charities, for the benefit of folks that truly need a helping hand. All it would have taken was an act of interest/kindness to give our estate to a member of our extended family.
Family is what you are born into; it's not your choice....