Parents validating my brothers religious psychosis

My brother has mental health issues and he's been saying how he got a message from God and is paranoid about bad things happening and that believes his neighbor is a witch. He's also saying God told him to sell all his stuff and carry a cross on his back. So he sold his things including his CAR and gave all the money to his friends. My brother has kids. He can't just sell all his stuff and fuck off. But he did and my other brother took in the kids ( their mom is dead). My parents and people in the church are supporting my brother doing this. I have nothing against religion but I think it's fucking dangerous when people are clearly having a mental health episode, just because they're claiming it's from God some people will validate their delusions. But if you say "Hades God of the underworld told me to do this." Now you're crazy and need to be placed in a mental health hospital. Religious psychosis has caused people to murder their own children because "God told me too." I think if someone is saying they are hearing voices even if they claim it's from God we should be concerned. But I don't feel like my parents are. My brother is so far away. I've tried to talk sense into him saying that I don't think God would want him homeless and abandoning his children who need him. But he insists this is how he's meant to be and his purpose. I'm not sure how to get him help if he doesn't believe he needs it