My parents are biphobic and homophobic. I want my brother to learn properly that not everything they tell him is true.

TW: Homophobic Slur

My mother doesn't believe in bisexuality. She believes that bi men are gay men who are using bisexuality as an excuse to pretend they have some semblance of their heterosexuality. She believes that bi women are straight women trying to get into the LGBTQ+ Community. I'm bi, and having to sit through that conversation was irritating, to say the least. My mother believes we are making up a bunch of sexualities, and from my understanding of her, she probably thinks there are only two genders too. I love my mom, and she doesn't hate anything LGBTQ+, she just doesn't know shit, to put it quite frankly. She tried to explain to me that all Trans people are gay. My father says the 'f' slur. He isn't as traditional, doesn't believe women should cook and stay behind to take care of the children, but at the same time doesn't believe in feminism. It's to be expected, I guess, and he isn't the type to tell me to wear dresses and not to wear pants, but the toxic masculinity is there, still. They both conform to most gender roles.

My brother listens to everything my father says and drinks it all in. He argues like my father's word is law. Women who like women are lesbians, men who like men are gay, women who talk or dress in a certain way are lesbians, men who wear dresses and skirts and talk and move in a certain way is gay, all that annoying bullshit.

I want to talk to him. I told myself I'd wait a few years when he starts forming his own opinions, but at the rate we're going, it's going to become instilled in his brain that this is right and this is how it goes. I don't wanna go on Twitter and find out my brother's laughing at a man in a dress. I don't want him to be a disrespectful little shit. I don't want him to be that insensitive person who doesn't know how to use pronouns.

He's only nine. Any advice?