This is an inheritance issue. My father-in-law inherited

This is an inheritance issue. My father-in-law inherited nothing from his parent's estate which is worth over 10 million. His elder brother inherited everything as that is the tradition in the family. Is this right? I had read this was not necessarily the case. He is an old man and I think he deserves a better standard of living. His nephew now lives in the manor house where my father-in-law grew up. He barely ever invites him round. My father-in-law is 89 and is the eldest member of the family and has to live in very basic accommodation. He has great grand-children but cannot host all his family at his cramped home. The cottage he lives in was owned by his elder brother (who got everything) and for many years my father-in-law even paid him rent! His elder brother died last year and he was not invited to the funeral but had to beg to come. His Nephew got most of the estate, following the family tradition but the tiny workers cottage where my father in law lives was given to all three of his elder brother's children in a strange break with tradition. I am sure he deserves more from his parents very sizable estate.