My granddad has 4 kids, each to whom he means to leave an equivalent portion of his resources. On the off chance that my dad, his child, kicks the bucket before him do I get my dad's cut or does my dad's cut get partitioned similarly among the excess kids? Is there a default lawful position?

My granddad has 4 kids, each to whom he means to leave an equivalent portion of his resources. On the off chance that my dad, his child, kicks the bucket before him do I get my dad's cut or does my dad's cut get partitioned similarly among the excess kids? Is there a default lawful position?