Pick up a friggin history book
Srsly, I'm bored of those people claiming a character-based game. Do you honestly think anyone cared about his family? Not even in Rome, let alone any other single tribe/kingdom during that era.
Quit on this, I could udnerstand some character thingies in democracies, but in the Seleucid kingdom? Wat? If you were a general, you couldn't just write something and say "Hi Antiochus, I feel like overthrowing you today and putting myself as a king,. Best regards, Ephialtes"
Your satrapy shouln't be inheritable and the king could just send you to prision if he felt like it. He was a god, you know?