"Él le dejó su fortuna a su hija."
Translation:He left his fortune to his daughter.
You need an indirect object (le, to him, to her) here because the verb demands it. It is not translated, but it is grammatically necessary. Literally, the sentence is: He to her his fortune left to his daughter. But in English we do not translate the indirect object.
But both hija and fortuna are feminine. And it can't be talking about him and his daughter or it would be les. Please explain this better.
You may want to read my explanation above. Other verbs that often demand indirect object pronouns are mandar, pedir, regalar, dar, traer, decir, contar, escribir, mostrar and others. Por ejemplo: Les escribo a mis amigos. I write to my friends. The "les" although not translated in English is necessary and not an option. José le da un beso a su bebe. José gives a kiss to his baby. The "le" is not translated, but it is not an option. This is Spanish grammar, and don't look for an English equivalent becuase there is none. Study the list of verbs (sometimes called exchange verbs) and notice how they work with the indirect object pronouns.
Note that "le" can also mean to him. He left his fortune to his son: E'l le dejo' su fortuna a su hijo.