My sister just came out as two spirit and it is the stupidest shit I've ever heard.

I assume she is not married otherwise that nonsense would have been beaten out of her already. In that case it's is your duty as the brother to correct her

Men are the managers of the affairs of women for that God has preferred in bounty one of them over another, and for that they have expended of their property. Righteous women are therefore obedient, guarding the secret for God's guarding. And those you fear may be rebellious admonish; banish them to their couches, and beat them. If they then obey you, look not for any way against them

An-nisa 4:34