Our Mum had a son to another man, before she married our Dad. He lived with our grandparents up until our grandmother passed away, and then he came to live with us. As far as we were concerned, he was our older brother. Both our Mum and he have passed away, and I want to complete his work - but I need to get permission? - from who do I need to get permission [he had children, but never married any of his children's mothers], so we are the next of kin [besides his children, I suppose] - can I complete his work?