My question involves adoption law for the State of: any?
So this isn't a real scenario, at least not for me, but I am curious about it.
If an older sibling has always taken care of a younger sibling (bc parents are too busy/too lazy), and I mean basically raised them as their own child, and the actual parents both die, could the older sibling (aged 18 or 19) get custody of the younger one? Especially if the younger sibling would prefer to stay with the older sibling.
Alternatively, could the parents specify in a will that the older sibling should get custody of the younger one? Would that be allowed?
If the sibling can't get custody, what would happen to the younger sibling? If they are going away to school (like a boarding school) would they be allowed to stay there?

