My father prefers my younger brother to me, what should I do?

I am from a well off, prominent family, and I am the eldest son. I was raised with the idea that one day I will inherit my father's property. I have two younger brothers (Louis and Philip) and three sisters (Jeanne, Marie and Isabelle), all to be provided for, of course, but the bulk was supposed to go to me. My father managed to get into a fight one day, and some of his bodyguards were beaten down, some ran away, only my brother Philip, then 14, stood by him. Not that it helped my father, because the thugs got him anyway, and we managed to bring him back to the family only some time afterwards. But since then, Philip is my father's favourite. Recently my father granted him a huge chunk of our property, to look after, and to do what he wanted with it, and to manage it as he pleases. I think it's unfair. I would have stand by my father, too, it's just that I was not near him when he was attacked, and what Philip did anyway? Shrieked "defend yourself, father, now to the right and now to the left"? Anybody can shriek. Yet he is now the golden son, the brave Philip, Philip the courageous, the bold. I am the eldest son, and I have nothing to govern, I am to wait till my father dies, Philip is already independent. I think, to be fair, I should be given something to govern, too. Maybe my father can even step down and let me lead the family business. I hinted about it to him and to his advisers, but no one listened and I don't want to talk about it directly, because it will look as if I wanted my father dead, or were envious of Philip. What should I do?