Utang na loob doesn't really mean debt to the family. It's more of a debt of the heart (inside is right), and it's an obligation that's so deeply ingrained that it never goes away.
Philippines society works on a constantly-shifting network of obligations, and utang can be incurred by anyone in relation to anyone else. Certainly the deepest debt is to the parent (for the privilege of being born), and then to the siblings and extended families but the network expands constantly and changes all the time.
GE
